Douglas works for a wide range of clients across the UK including national agencies, local authorities, universities, private businesses, and other environmental professionals. Previous clients include:
- Buchan Landscape Architecture
- Cass Associates
- Countryscape
- Circle Design
- Devon County Council
- Dorset Area of Outstanding Natural Beauty Partnership
- Geddes Planning
- Janet Falkingham Consultancy
- Land Use Consultants
- Loch Lomond & The Trossachs National Park Authority
- Locogen
- Natural England
- Northern Ireland Environment Agency
- Scottish Natural Heritage
- TNEI
- University of Edinburgh
