| 21 Augusta Road RTM Company Limited | Swaffham | 2012 |
| 21 Baldry Gardens Freehold Limited | London | 2018 |
| 21 Barker Gate Management Company Limited | Nottingham | 1999 |
| 21 Barnsbury Street Management Limited | London | 1984 |
| 21 Barter Street RTM Company Ltd | Maidstone | 2021 |
| 21 Baslow Road (Eastbourne) Freehold Limited | Eastbourne | 2023 |
| 21 Bath Buildings Management Limited | Woodford Green | 2004 |
| 21 Bath Street (Brighton) Limited | Brighton | 2017 |
| 21 Bedford Place Brighton Limited | Brighton | 2013 |
| 21 Bellevue Crescent Clifton Ltd | Avon | 1986 |
| 21 Belvedere (Bath) Limited | Bath | 1986 |
| 21 Belvedere Terrace Freehold Company Limited | Shoreham-By-Sea | 2020 |
| 21 Bincleaves Road Weymouth Management Company Limited | Weymouth | 2016 |
| 21 Blake Hall Road Management Limited | London | 2001 |
| 21 Blenheim Road (Management) Company Limited | Bristol | 1976 |
| 21 Bloomfield Avenue (Management) Limited | Bath | 1988 |
| 21 Bloomfield Road Limited | Bath | 2017 |
| 21 Blythe Hill (Freehold) Limited | London | 2013 |
| 21 Bolton Gardens Limited | London | 2002 |
| 21 Bradiston Road Limited | London | 2011 |
| 21 Brechin Place Freehold Limited | London | 2009 |
| 21 Brighton Road Management Company Limited | South Croydon | 2014 |
| 21 Broadwater Down Management Company Limited | Tunbridge Wells | 2010 |
| 21 Brock Street (Bath) Limited | Corsham | 1983 |
| 21 Brookfield Road Management Company Limited | London | 2018 |
| 21 Brunswick Square Limited | Hove | 1996 |
| 21 Buckingham Place (Brighton) Limited | Hove | 2006 |
| 21 Bulstrode Street Limited | | 2007 |
| 21 Burma Road Management Company Limited | Cambridge | 1983 |
| 21 Burton Crescent Management Limited | Leeds | 1992 |
| 21 Cambridge Green RTM Company Limited | London | 2022 |
| 21 Cambridge Road Hove Limited | East Sussex | 2001 |
| 21 Canterbury Road Limited | Margate | 2005 |
| 21 Cardigan Road Residents Company Limited | Thames Ditton | 1999 |
| 21 Carisbrooke Road RTM Company Limited | Hastings | 2014 |
| 21 Carlisle Road (Hove) Limited | East Sussex | 1994 |
| 21 Carlton Road North Management Co Ltd | Weymouth | 1997 |
| 21 Carter Avenue Management Limited | Shanklin | 2011 |
| 21 Castletown RD (Freehold) Ltd | London | 2005 |
| 21 Catherine Road Limited | Surbiton | 2010 |
| 21 Cavendish Road Limited | London | 2004 |
| 21 Charles Road Management Company Limited | St Leonards On Sea | 2017 |
| 21 Chase Green Management Limited | Enfield | 1980 |
| 21 Chesham Place Limited | London | 2006 |
| 21 Chesham Place RTM Company Limited | Brighton | 2022 |
| 21 Chetwode Road Management Company Limited | London | 2025 |
| 21 Chobham Road RTM Company Limited | London | 2013 |
| 21 Clarence Avenue Management Company Limited | Croydon | 2016 |
| 21 Claverton Freehold Limited | Rugby | 2024 |
| 21 Cleveland Square Limited | Potters Bar | 1987 |
| 21 Cleveland Street Management Limited | Croydon | 2023 |
| 21 Clifton Gardens Management Limited | Ashford | 1991 |
| 21 Coleherne Road Limited | London | 2001 |
| 21 Colehill Lane Management Company Limited | London | 2010 |
| 21 Colenso Road RTM Company Limited | London | 2009 |
| 21 Coley Hill Management Company Limited | Cambridge | 2004 |
| 21 College Road Limited | Chichester | 2014 |
| 21 Collingham Gardens Management Limited | London | 1998 |
| 21 Collingham Road Limited | United Kingdom | 2004 |
| 21 Comyn Road Management Company Limited | London | 1998 |
| 21 Connaught Avenue Management Company Limited | Plymouth | 2001 |
| 21 Courtfield Gardens Limited | London | 2006 |
| 21 CP Ltd | Woking | 2026 |
| 21 Cranbourne Road Management Limited | Manchester | 2001 |
| 21 Craneswater Park (Freehold) Limited | Drayton | 2015 |
| 21 Craven Hill Management Limited | London | 1984 |
| 21 Crescent Road Limited | London | 1991 |
| 21 Cromwell Road Limited | Plymouth | 2011 |
| 21 Crouch Hall Road (Management) Limited | London | 1993 |
| 21 Culmington Road Ealing Ltd | London | 1997 |
| 21 Culverley Road Management Limited | Bromley | 2015 |
| 21 Dane Road (Management) Limited | St. Leonards-On-Sea | 2004 |
| 21 Davigdor Road Limited | Brighton & Hove | 2009 |
| 21 Denbigh Street Management Limited | London | 2006 |
| 21 Denmark Terrace Brighton Limited | Hove | 2018 |
| 21 Devonshire Place Limited | Wirral | 1996 |
| 21 Devonshire Road (Hatch END) RTM Company Limited | Harlow | 2006 |
| 21 Disraeli Road Limited | | 2003 |
| 21 Ditchling Rise Limited | Brighton | 2020 |
| 21 Dollis Avenue Limited | London | 2020 |
| 21 Dorset Road Management Company Limited | London | 2014 |
| 21 Dragon Avenue (Harrogate) Limited | North Yorkshire | 2005 |
| 21 Dukes Road Residents Association Limited | Reading | 2005 |
| 21 Dundonald Road Ltd | Clifton | 2009 |
| 21 Earl Street (Hastings) RTM Company Limited | Eastbourne | 2025 |
| 21 Earls Avenue Ltd | Folkestone | 2016 |
| 21 Earlsfield Road Limited | London | 1991 |
| 21 Eaton Place Limited | London | 2017 |
| 21 Eccleston Square Associates Limited | London | 2014 |
| 21 Edith Road Limited | Bath | 2012 |
| 21 Egmont Road Sutton Management Company Limited | Sutton | 1992 |
| 21 Eldorado Road Limited | Cheltenham | 2016 |
| 21 Elgin Crescent Limited | Tetbury | 1999 |
| 21 Eliot Park Freehold Company Limited | London | 2024 |
| 21 Ellison Road Limited | London | 2022 |
| 21 Elmbourne Road Management Limited | London | 2023 |
| 21 Elmcourt Road Limited | London | 2002 |
| 21 Embankment Gardens (Freehold) Limited | Angmering | 2006 |
| 21 Ennismore Avenue Management Limited | Surrey | 1997 |
| 21 Enys Road (Eastbourne) Limited | Eastbourne | 2004 |