| Dorey & Lawson Limited | Plymouth | 1929 |
| Dorgan Sports Horses Limited | Billingshurst | 2005 |
| Doris Farming Limited | Penkridge | 2020 |
| Dorking Community Orchard CIC | Dorking | 2009 |
| Dormers Farm Limited | Burgess Hill | 2017 |
| Dormfresh Limited | Perth | 2000 |
| Dorset & Somerset Estates Limited | Dorchester | 1964 |
| Dorset Aquatics Ltd | Templecombe | 2010 |
| Dorset Cattery Limited | Dorchester | 2024 |
| Dorset Conservation Contractors Ltd | Exeter | 2023 |
| Dorset Coppice Group Limited | Blandford Forum | 2003 |
| Dorset Game Services Limited | Poundbury | 2004 |
| Dorset Herbs & Essences Farm Limited | Wimborne | 2017 |
| Dorset Horn and Poll Dorset Sheep Breeders' Association | Dorchester | 1891 |
| Dorset Knapp Ltd | Dorchester | 2025 |
| Dorset Lavender Farm Project Limited | Sturminster Newton | 2010 |
| Dorset Plant Co. Limited | Wimborne | 2008 |
| Dorset Planters Ltd | Poole | 2019 |
| Dorset Shellfish Company (Poole) Ltd | Poole | 2018 |
| Dorset Snails Limited | Wimborne | 2012 |
| Dorset Springs Limited | Dorchester | 2021 |
| Dorset Treeworx Ltd | Portland | 2009 |
| Dorsetshire Limited | Dorset | 2003 |
| Dorsington Farms Limited | Stratford-Upon-Avon | 1995 |
| Dorstone Agroforestry Limited | Cheltenham | 2024 |
| Dorstone Court Farms Limited | Hereford | 2024 |
| Dorwaila Group of Companies Limited | Barking | 2020 |
| Dostel Ltd | Bristol | 2023 |
| DOT PAR Limited | Northwood | 2021 |
| Dotty and Quinn Pet Co Ltd | Newark | 2026 |
| Double 'R' Farm Company Limited | Cheltenham | 1979 |
| Double Diamond Dressage Ltd | Malmesbury | 2023 |
| Double Diamond Stables Ltd | Malmesbury | 2023 |
| Double Dikes Fishing Ltd | Fraserburgh | 2022 |
| Double M Stud Limited | Gillingham | 2017 |
| Double Red 359 Ltd. | London | 2009 |
| Doubleday (Farms) Limited | Colchester | 1962 |
| Douganhill Farms Limited | London | 2025 |
| Dougarie Estate Limited | Isle Of Arran | 2020 |
| Douglas and Angus Estates. | Edinburgh | 1937 |
| Douglas Brown Contracting Limited | Lockerbie | 2026 |
| Douglas Farms | Carlisle | 2009 |
| Douglas Inglis Consultancy Ltd | Woodbridge | 2020 |
| Douglas Livery Ltd | Hull | 2024 |
| Douglas ORR & Company Limited | Edinburgh | 1998 |
| Douglas Timber Harvesting Ltd | Glenurquhart | 2013 |
| Dougold Mussels Ltd | Co. Londonderry | 1999 |
| Dove Agriculture (Eastern) Limited | Bishops Stortford | 2014 |
| Dove Fields Ltd | Ashbourne | 2023 |
| Dove Syke Limited | Keighley | 2018 |
| Dove's Farms Limited | Goffs Oak | 1956 |
| Dovecote Lakes Limited | Shifnal | 2015 |
| Dovedale Farms Limited | Letchworth Garden City | 2010 |
| Dovenby Game Limited | Cockermouth | 2015 |
| Dovenby Sporting Club Limited | Cockermouth | 2015 |
| Doveside Limited | Derby | 2017 |
| DOW (Scotland) Limited | Aberdeenshire | 2017 |
| Dowbiggin Agriculture Ltd | Clitheroe | 2022 |
| Dowdeswell & Dowdeswells Ltd | Llanymynech | 2019 |
| Dowdeswell Conservation (Trading) Limited | Cheltenham | 2021 |
| Dowdeswell Conservation Limited | Cheltenham | 2014 |
| Dowdeswell Forestry Limited | Cheltenham | 2017 |
| Dower House Farms Ltd | Uckfield | 2023 |
| Dowhall Farms Limited | Pocklington | 2021 |
| Down Farm Market Garden Ltd | Winkleigh | 2017 |
| Down Mussels Ltd | Newry | 2003 |
| Down to Earth Landscaping (Wales) Limited | Pembrokeshire | 2016 |
| Down to Earth Trees Ltd. | Chislehurst | 2012 |
| DOWN2EARTH Consulting Limited | Princes Risborough | 2002 |
| Downcourt Limited | Chatham | 2018 |
| Downe Livery Ltd | Orpington | 2020 |
| Downes Equine Ltd | Stoke-On-Trent | 2021 |
| Downey Fishing Company Ltd | Newhaven | 2015 |
| Downham Cottage Care Farm Ltd | Woodbridge | 2011 |
| Downie Farming Company Limited | Ballater | 2019 |
| Downing Bloodstock Limited | Droitwich | 2019 |
| Downland Deer Reserves Limited | Hereford | 2015 |
| Downland Marketing Limited | Carlisle | 1968 |
| Downlands Equestrian Limited | Winchester | 2003 |
| Downlands Tree Surgery Ltd | Warminster | 2008 |
| Downs View Nurseries Ltd. | Chichester | 2003 |
| Dowrich Farms Limited | Taunton | 1955 |
| Doyen Financial Limited | Aylebury | 2015 |
| Doyle Farming Limited | Windsor | 2022 |
| DP & FM Day & SON Ltd | Middlesbrough | 2002 |
| DP Farriers Ltd | Worcester | 2017 |
| DPF Woodlands Limited | Hungerford | 2020 |
| DPG Services Limited | Chichester | 2021 |
| DPJ Equine Limited | Chorley | 2022 |
| DPS Forestry & Land Management Limited | Maldon | 2014 |
| DQC Equine Limited | Durham | 2022 |
| DR & DP Jones Ltd | Porthmadog | 2017 |
| DR & HM Horsley Limited | Carlisle | 2003 |
| DR 89 Ltd. | Fraserburgh | 2010 |
| DR Beynon's BUG Farm Limited | Haverfordwest | 2013 |
| DR Dyer's Dairy Goat Farm Limited | Enniskillen | 2018 |
| DR Errigal Farms Ltd | Dungannon | 2025 |
| DR Green Tree Care Ltd | Lisburn | 2019 |
| DR Herbal Ltd | London | 2019 |
| DR Jacques & SON Limited | Gainsborough | 2020 |