Ben is the Founder and Managing Director of Mainer Associates and the creator of CarbonCentric, the firm’s advanced carbon‑management platform. A certified BREEAM Advisory Professional, he directs the strategic vision, commercial growth and operational delivery of the business, ensuring a consistently high level of technical and strategic excellence across all services.
With extensive experience leading multimillion‑pound real estate projects for both private‑sector clients and Government Departments, Ben brings strong commercial understanding, sector insight and forward‑thinking leadership to every engagement. His career has centred on shaping robust sustainability, environmental and carbon strategies; building specialist technical teams from inception; and developing innovative technology solutions that address some of the built environment’s most complex value‑chain challenges.
Ben’s combination of industry expertise, strategic clarity and commitment to innovation continues to drive Mainer Associates’ growth and its impact across the sustainability sector.

Ben Wells

Dom Wintie

Dom leads the Life Cycle Assessment function at Mainer Associates with a laser focus on embodied carbon performance. As a qualified RICS Whole Life Carbon Assessment (WLCA) Practitioner and certified BREEAM Advisory Professional, he brings deep technical expertise across Whole Life Carbon Assessments, BREEAM LCA and LCC, and advanced embodied‑carbon consultancy and management.
He partners with commercial clients and Government Departments on major multimillion‑pound developments, delivering robust carbon modelling, value‑chain carbon analysis and low‑carbon optimisation strategies. Dom also shapes organisation‑wide carbon methodologies, builds advanced WLCA capabilities and pioneers tech‑enabled solutions designed to address some of the built environment’s most complex embodied carbon challenges.

Ben Sidebottom

Ben leads the Sustainability Assessment team at Mainer Associates, bringing over two decades of hands‑on experience in the sustainability sector. As one of the UK’s first BREEAM Accredited Professionals, he’s been at the forefront of shaping high‑performance, future‑focused buildings across the UK and the Republic of Ireland.
Ben has delivered some of the region’s most successful sustainable projects, ranging from small commercial units to major city‑centre hospitals. His expertise spans all sectors and covers both new‑build and refurbishment developments.
Known for his proactive, pragmatic and collaborative approach, Ben builds strong working relationships with clients and design teams alike - helping drive practical, impactful sustainability outcomes on every project.

Alex Thompson

Alex is a certified BREEAM Advisory Professional, who brings a strong architectural foundation that elevates his approach to sustainability and carbon analysis. His deep understanding of building strategy and performance underpins his work across Embodied Carbon, Whole Life Carbon Assessments (WLCA) and Life Cycle Costing (LCC), where he develops clear, practical and client‑focused processes that simplify complex technical requirements.

Before joining Mainer, Alex worked at BDP, collaborating closely with clients and successfully certifying numerous projects under BREEAM UK New Construction. He has delivered both assessments and broader sustainability strategies across a wide range of project types, supporting design teams in achieving ambitious environmental and performance outcomes.

Alex’s blend of technical expertise, design‑led thinking and advisory‑level certification enables him to drive meaningful, well‑integrated sustainability outcomes across every project he supports.

Senior Sustainability Consultant

Oscar Holden

Oscar is the newest member of the Mainer Associates team, joining as a Senior Sustainability Consultant and bringing nearly a decade of experience delivering high‑impact sustainability and ESG outcomes across the UK and Europe. His expertise spans BREEAM assessments, planning statements, bespoke ESG strategies and Whole Life Carbon (WLCA) reporting for both new‑build and refurbishment projects.

Combining strong technical capability with clear stakeholder communication and effective project management, Oscar has a proven track record of delivering complex, data‑driven sustainability work. His portfolio includes developing tailored strategies and reporting for large‑scale masterplans, as well as certifying some of the highest‑rated BREEAM‑certified buildings in Ireland.

Oscar’s ability to balance analytical depth with practical, client‑focused delivery enables him to drive robust, actionable sustainability results across every project he supports - making him a valuable addition to the growing Mainer Associates team.

Senior Sustainability Consultant

Lucy Summerell

Lucy joined Mainer Associates as a graduate Sustainability Consultant after completing her Master’s in Management and Sustainability at Manchester Metropolitan University. With an academic foundation that spans both creative and analytical disciplines - beginning with a BA in Art and Design from the University of Leeds - Lucy brings a unique perspective to sustainability in the built environment.

Motivated by a desire to encourage wider engagement with climate action and sustainable development, Lucy explored different pathways before choosing to focus her career on sustainability consultancy. Her interest in the sector deepened during her research into built‑environment sustainability practices, culminating in a presentation on the viability of achieving the UK’s net‑zero 2050 target during her application to Mainer.

At Mainer, Lucy is keen to build strong practical skills across sustainability assessments and contribute to meaningful, evidence‑based climate action through her project work.

Sustainability Consultant

Meet the Experts

Founder and Managing Director