Who We Are

Wilfred Sleeman. Wilfred studied management science at Vrije Universiteit, Amsterdam, and has more than 20 years experience as a business consultant. He helps organizations optimize their business processes, organizational structures and IT-systems. Since 2016, he has helped organizations to think about their non-financial reporting and how non-financial topics (i.e. environmental, social and governance topics, or ESG-topics) affect business processes such as risk management and stakeholder management. Wilfred gained experience in for profit settings (e.g. Martinair, Heineken and ABN AMRO), not for profit settings (e.g. World Wildlife Fund, Centre for Indications in Health Care (CIZ)), and government (municipality of The Hague).

As a Certified Management Accountant, he also worked as an (interim) finance manager and has in-depth knowledge of Order-to-Cash, Procure-to-Pay and Record-to-Report processes. Wilfred is an inquisitive, self-motivated learner, with an eye for practical theory. His mission has always been to create lasting value for organizations. The last years he has learned that this day and age increasingly calls for integrating social, environmental and governance topics in business processes, risk management and strategic decision making.

Johan Booij. As an associate to Sleeman Consulting, Johan and Wilfred have worked together closely on the topic of non-financial information.Johan studied Economics at the University of Amsterdam. He started his professional career at Magnus Management Consultants where he held several (management) positions and worked for customers like Unilever, Heineken and Sony. He then worked as a business analyst and project manager in international teams for Hewlett Packard before moving to the non-profit sector. Within the Dutch branch of the World Wildlife Fund, Johan worked successively as International Finance Manager and Head of the Planning, Monitoring and Evaluation unit. He was member of the committee deciding on the funding for conservation programs, co-led the development of the conservation strategy, and set up a planning, monitoring and evaluation framework.

As of 2016 Johan works as an independent consultant. Besides providing support on planning, monitoring and evaluation issues (mostly to NGO’s), he combines his experiences within the for profit sector and WWF to help organizations with the use and reporting of non-financial information (i.e. environmental, social and governance topics).

Johan has over 20 years of experience in the design and management of processes and standards and the implementation of financial and project systems. Other areas of expertise include strategy and planning, monitoring and evaluation, financial and non-financial reporting, project management, risk management and conservation and sustainable development topics.

Jaap Vonk. Jaap is an associated partner to Sleeman Consulting for Sustainable and Circular Procurement. Jaap’s vision; ‘If you are able to organize procurement transparent, goal-oriented, flexible and sustainable, it will be a major contribution to the continuity and profitability of the company.’

Jaap has more than twenty years experience in purchasing management at organizations such as Martinair, Fokker, Heineken, and ANWB. On top of that, Jaap teaches Corporate Social Responsibility (CSR/MVO) and Sustainable Procurement (MVI) at NEVI, the leading knowledge network for procurement, contract and supply management.

As an experienced professional sailor, he is able to steer your purchasing organization towards professionalization and your organization towards sustainability. Jaap’s technical background comes in handy in technically complex environments. His approach is systematic, pragmatic and result-oriented. He delivers added value where teamwork, creativity, enthusiasm and sustainability are the core values.

Didi Hoezen. Didi Hoezen is an associate to Sleeman Consulting for integrated reporting and sustainability management. Didi is a passionate, dedicated, all-round project manager specialized in integrating Sustainability and Circularity strategic priorities, processes, and reports of organizations. She possess an immense drive, enthusiasm and thoroughness which paves the way for her to empower teams and stakeholders, and promote change for the benefit of social impact and organizational opportunities. 

She assists companies with their sustainability strategy, circular transition, Sustainable Development Goals, stakeholder management, sustainable supply chain management, impact measurement and integrated reporting efforts. Didi believes in focus, balance and an honest story when it comes to Sustainability and Circularity: focus on where an organization can make a difference socially, and what suits the core business and role in the supply chain; balance between profitability and sustainable value; honest in the sense of fact-based (as opposed to anecdotal) stories  looking at the social role, achievements and dilemmas of organizations.

Didi has over 12 years consultancy and audit experience at the ‘big four’ audit firms and started 2Bhonest in 2017.  During her career, she worked as a sustainability project manager on several large (inter)national projects, and supported numerous companies such as Bavaria, ING, SITA, TBI, NN, ASML, Vopak, Corbion, DSM, AkzoNobel, Hutten and TNT.