| Dhoqoshay Development Organisation Ltd | London | 2025 |
| DHS Educational Foundation Limited | Durham | 2007 |
| DHU Consulting Ltd | Larne | 2019 |
| Dhvani London Ltd | London | 2021 |
| DHXA1 Ltd | London | 2025 |
| DHY Teachers Training Academy (UK) Ltd | Eastbourne | 2017 |
| Dhyey Tuition Ltd | Feltham | 2023 |
| DHZ Group Ltd | London | 2025 |
| DI Macdonald Limited | Witney | 2025 |
| DI Turi & Veness Limited | Fareham | 2011 |
| Diabetes Performance Coaching | Belfast | 2016 |
| Diadems Childcare Ltd | London | 2019 |
| Diafootcare Limited | Rochester | 2025 |
| Dial Telecom Ltd | Manchester | 2014 |
| Dialectic Education Limited | London | 2024 |
| Dialled in Coaching Ltd | Aberdeen | 2023 |
| Dialledinbymaginn Ltd | Newry | 2024 |
| Dialogic Space Ltd | Cambridge | 2024 |
| Dialogic Training Ltd | London | 2022 |
| Dialogics Consultancy Limited | London | 2004 |
| Dialogue Consultants Limited | Totnes | 2013 |
| Dialogue Consulting Ltd | Pontypool | 2004 |
| Dialogue for Diversity | Armagh | 2011 |
| Dialogue Fosters CIC | Sunderland | 2021 |
| Dialogue Language Training Limited | Radstock | 2021 |
| Dialogue Society | London | 2005 |
| Dialogue UK Limited | London | 1991 |
| Dialogue Works Ltd | Cramlington | 2018 |
| Dialysis UK CIC | Leicester | 2021 |
| Diamant Capital Limited | Enfield | 2022 |
| Diamant Femme Ltd | London | 2026 |
| Diamond Academy Football Club CIC | Birmingham | 2019 |
| Diamond Athlete Limited | Kington | 2026 |
| Diamond Cleaning Training Academy NI Ltd | Belfast | 2025 |
| Diamond Clinical Services Ltd | Stalybridge | 2025 |
| Diamond College of London Ltd | London | 2022 |
| Diamond Days Childcare Ltd | Luton | 2023 |
| Diamond Driver Training Ltd | Leicester | 2010 |
| Diamond Driving School Ltd | Brentwood | 2011 |
| Diamond Edge Martial Arts CIC | Smethwick | 2025 |
| Diamond Educare Limited | London | 2019 |
| Diamond Education Hub Limited | Birkenhead | 2017 |
| Diamond Education Ltd | Cheam | 2025 |
| Diamond Education Partners Ltd | Winchester | 2011 |
| Diamond Elite Gymnastics Club Ltd | London | 2025 |
| Diamond Hall Infant Academy | Sunderland | 2013 |
| Diamond International Sports Academy Ltd | Poole | 2019 |
| Diamond League Agency Ltd | London | 2024 |
| Diamond Learning Centre Ltd | London | 2019 |
| Diamond M Aesthetic Ltd | Brighton | 2022 |
| Diamond Minds Consultancy Ltd | London | 2018 |
| Diamond Pathways C.I.C. | St. Albans | 2026 |
| Diamond Plus Research Ltd | Gateshead | 2026 |
| Diamond Preschool Ltd | Slough | 2014 |
| Diamond Property Network Limited | Nottingham | 2022 |
| Diamond Property Training Group Limited | Caldicot | 2025 |
| Diamond Ridge Consultancy Ltd | London | 2025 |
| Diamond Skin Training Ltd | Stalybridge | 2023 |
| Diamond Smiles Academy Ltd | Edinburgh | 2024 |
| Diamond Sports Coaching Ltd | Stratford-Upon-Avon | 2018 |
| Diamond Sports Consultancy Ltd | London | 2018 |
| Diamond Sportz Ltd | Ilford | 2024 |
| Diamond Swim Academy Ltd | Telford | 2014 |
| Diamond Training Solutions Ltd | Broughty Ferry | 2025 |
| Diamond Training SW Ltd | Paignton | 2021 |
| Diamond Tutors Ltd. | Croydon | 2020 |
| Diamond YOU Projects CIC | Kington | 2019 |
| Diamonds Community Learning Project CIC | Birmingham | 2017 |
| Diamonds Elite and Recreational Cheerleading C.I.C. | Consett | 2026 |
| Diamonds in the Sky Ltd | London | 2012 |
| Diamondvalue Coaching Limited | Chelmsford | 2013 |
| Diamondz School of Dance Ltd | Sleaford | 2021 |
| Dian Club Limited | Harrow | 2023 |
| Diana Aesthetics Ltd | Worthing | 2021 |
| Diana Award | London | 2006 |
| Diana Catalina Ltd | Hornchurch | 2022 |
| Diane Gardner Literacy Consultancy Ltd | Glasgow | 2018 |
| Diane Jeffries Consultancy Limited | East Boldon | 2022 |
| Diane Rochford Limited | Stockport | 2012 |
| Diane Turner Limited | Middlesbrough | 2017 |
| Diane's Nurseries Ltd | Selby | 2016 |
| Dianne Shackleton Ltd | London | 2016 |
| Diary of a Barrister Ltd | Leeds | 2026 |
| Diary of Two Doctors Ltd | Craven Arms | 2025 |
| Dias Academy Limited | Leicester | 2025 |
| Diaspora Development Hub Ltd | Barnet | 2025 |
| Diaspora Entertainment Limited | London | 2025 |
| Diaspora House Ltd. | London | 2020 |
| Diaspora Impact CIC | Coventry | 2026 |
| Diaspora Impact Group | London | 2021 |
| Diaz Martial Arts Ltd | Barnet | 2022 |
| Diben CYF | Swansea | 2022 |
| Dice Global Services Ltd | London | 2023 |
| Dice Mentoring Ltd | Swindon | 2026 |
| Dicing With Life CIC | Romford | 2020 |
| Dicker Enterprises Limited | Hailsham | 1989 |
| Dickinson in England Limited | Norwich | 2019 |
| Dickinson James Limited | Clapham | 2012 |
| Dickinson School Consulting Limited | Harrogate | 2009 |
| Dickory Dock Nursery | Sheffield | 2003 |