About Us

Since 2010, Mantle has been working with industry-leading organisations to give their people the leadership edge.

What we believe in

At Mantle, we’re committed to working together with our clients to achieve the best possible leadership development outcomes. To do that, we focus on:

  • Impact: Making a real difference
  • Collaboration: Working as partners and making it easy
  • Being real: Focusing on practical solutions that work
  • Growth: Continuing to learn and adapt
  • Performance: Being tuned-in, responsive and at the top of our game

Our team

Our fantastic leadership development community is made up of experienced facilitators, learning designers and coaches, who focus on providing the very best experience for learners, whether working virtually or face to face.   We’re all passionate about enabling leaders to be the best versions of themselves and empowering them to thrive in today’s busy and ever-changing world.

Graham Hart

A founding Director of the business, Graham has more than twenty-five years’ experience working in operations, human resources and management consulting roles.  His relentless curiosity and creativity are two of the main reasons Mantle continues to grow its impact on the leadership world.

Denise Carter

Co-founder, Denise has more than 30 years’ experience in leading and developing people. Her career has seen her in roles ranging from an Officer in the armed forces, to senior group learning and development positions in some of the UK and New Zealand’s largest organisations. Her focus on relationships supports long-term partnerships with our clients, some of whom have been with us since we started.

Ruth Donde

Ruth is part of the Mantle leadership team and is the Director responsible for driving the amazing standards of delivery we are known for. She is passionate about leadership development, and the impact of personal and professional development on individuals, relationships and organisational outcomes. Her commitment to continuous learning is also applied to ensuring our own team’s capabilities are constantly evolving.

Anton Ashcroft

Passionate about fostering great leaders, Anton has many years of experience facilitating both individuals and groups through the process of change, personal development and conflict resolution. With a tertiary qualification in psychology, one of his unique strengths is his ability to take complex ideas, such as the neuroscience principles that underpin our approach, and turn them into practical tools and techniques.

Lettie Dalton

A highly experienced, commercially astute and passionate facilitator, coach and trainer, Lettie has a proven background in working with corporate organisations worldwide to empower, motivate and engage people. Lettie loves to experiment, operating within the learner’s context and gently pushing them to try new things in order to gain fresh insights.

Mark Wirihana

Mark is a warm relationship builder and a very effective facilitator and designer. Throughout his life, he has been involved in Tikanga Maori and has been influenced by the initial Kingitanga to modern Maori leaders (Ngata, Carroll, Ratana and TePuea Herangi). Passionate about building bridges between cultures and encouraging broader perspectives Mark is forever developing new skills and capabilities.

Nikki Hommes

Nikki has a Masters of Business Administration (MBA) Degree in coaching and mentoring and is a qualified life, executive and workplace coach.  In addition to being an NLP Practitioner, she is a Master TetraMap facilitator, Talent Dynamic Flow Consultant & Ignition! Youth Coach.  Enthusiastic and energetic, Nikki’s passion for learning translates to highly motivating and encouraging environments.

Saskia Clements

Saskia is passionate about unlocking potential in individuals and organisations. She is a highly respected facilitator, coach, and mentor. Saskia's positive and empathetic style allows her to challenge and encourage learners to harness insights and reach new levels of performance.

Rochelle Trail

Rochelle has a passion for knowledge acquisition, understanding human behaviour and people development.

With qualifications in natural health, nutrition and psychology, she takes a holistic perspective when working with clients, considering all aspects of their wellbeing while working with them to achieve leadership development goals. 

Jon Dunning

Jon is an experienced people leader, facilitator and coach. Whether in a small team environment or a large, complex and diverse organisation, Jon looks for opportunities to translate the strategic into operational in order to meet our clients’ ultimate goals. His focus on developing sound partnerships with our clients is a key factor in the sustainable outcomes they achieve.

Roxy Pringle

Roxy is the administrative guru for the Mantle team, providing day to day backup for the Directorship.

She has a BA in Sociology and Criminology, and a varied background in administration, bookkeeping and events management giving her a vast range of skills and knowledge to impart. Give it to Roxy and it gets done!


Julia Wiegandt-Goude GM – People, Culture and Safety
“It’s been a hugely successful programme and has had a fantastic positive impact on our people, creating a set of tools that help SPCA deliver on our mission and purpose.”
Heart Foundation NZ
People Leaders
‘Thank you so much for facilitating a valuable growth experience.’ ‘Invaluable, fun, interactive and ‘real’ workshops.’
Marina Dzepina ASB Organisational Development Specialist
“One of the benefits of using the leadership consulting services of Mantle is we now have leaders who have a vision and personal route map for self-improvement. You are very easy to work with and believe in partnership with your clients. Graham and Denise are constantly engaging on leading edge thinking and are very willing to share and explore new ideas in the field of leadership development.”
The Leader Team Leader
“I now think of myself as a leader and understand how I can influence our future at BCS.”
Jenni Coles Ex Director, Bupa Care Services
“We decided to use the services of Mantle because we liked how well you listened and got to the heart of our issues and understood our current reality. You have employed a partnership design methodology and successfully designed and implemented the programme. We now have leaders who have a vision and personal route map for self-improvement. We have increased performance in teams, change leadership and engagement.”
Stephanie Field HR Manager
Mantle established themselves as a key strategic partner, playing an integral role in a number of successful OD initiatives across both the NZ and Australian businesses.
Auckland Kindergarten Association
Tanya Harvey CEO Auckland Kindergarten Association
“You quickly get under the skin of the organisation and you offer leading edge thinking on development and applying neuroscience. Your services are practical and pragmatic not academic or heavy on theory. We now have more confident and engaged leaders and we are growing our leadership mind-set and opportunities. You were quickly able to add value up front and I like your flexibility and collegial approach.”
Mercury Programme participant
“I’ve witnessed well-meaning performance “feedback” having the unintended consequence of actually detracting from a team’s ability to reach its potential… I now have a better understanding of how to keep a team focussed on improving rather than just proving when reviewing performance.”


Phone: 021 833 841

Email: [email protected]

Social Links