| 21 Epsom Road RTM Company Limited | Stroud | 2018 |
| 21 Ethelbert Crescent Freehold Limited | Sittingbourne | 2018 |
| 21 Fairmile Avenue RTM Company Limited | London | 2020 |
| 21 Falkland Management Limited | | 1989 |
| 21 Farlton Road Management Limited | Wallington | 2014 |
| 21 Fawley Road Limited | West Hampstead | 2021 |
| 21 Fawnbrake Avenue Management Limited | London | 2019 |
| 21 Fieldhouse Road Limited | London | 2011 |
| 21 First Avenue (Hove) Limited | Hove | 2003 |
| 21 Fitzhamon Embankment Company Limited | Cardiff | 2005 |
| 21 Fitzjohn's Avenue Limited | Stanmore | 1965 |
| 21 Fordingley Road Limited | Guildford | 2026 |
| 21 Fordwych Road-Live Limited | London | 2006 |
| 21 Fort Crescent Owners Limited | Kent | 2020 |
| 21 Fourth Avenue London W10 Limited | London | 2010 |
| 21 Frankfurt Road Limited | London | 2023 |
| 21 Franklin Road (Brighton) Limited | Brighton | 2013 |
| 21 Galesbury Road Limited | Eye | 2016 |
| 21 Gambetta Street Freehold Limited | Yeovil | 2014 |
| 21 Garlands Road RTM Company Limited | Weybridge | 2022 |
| 21 Gillian Street RTM Company Limited | London | 2010 |
| 21 Gladstone Road Ltd | West Byfleet | 2018 |
| 21 Glengall Road Freehold Company Limited | London | 2022 |
| 21 Glenrosa Street Freehold Limited | London | 2020 |
| 21 Glenton Road Ltd | Lewisham | 2010 |
| 21 Gordon Road (Chiswick) Limited | Harrogate | 2002 |
| 21 Grange Park Freehold Co Limited | Amersham | 2021 |
| 21 Greencroft Gardens Limited | Oxford | 2000 |
| 21 Grosvenor Crescent Ltd | Scarborough | 2025 |
| 21 Grosvenor Place (Bath) Limited | Bristol | 1983 |
| 21 Haldon Road Limited | London | 1986 |
| 21 Hampstead Hill Gardens Limited | London | 1997 |
| 21 Hampstead Lane Service Company Limited | | 1962 |
| 21 Hampton Park Management Company Ltd | Bristol | 2018 |
| 21 Hampton Place Limited | East Sussex | 2000 |
| 21 Hardwicke Road Freehold Limited | Coventry | 2010 |
| 21 Helix Road Limited | London | 2025 |
| 21 Heywood Limited | London | 2022 |
| 21 Hinguar Street RTM Company Limited | Leigh On Sea | 2018 |
| 21 HL RTM Company Limited | London | 2025 |
| 21 Holland Road, Hove Limited | Worthing | 1993 |
| 21 Holmewood Road Limited | London | 2009 |
| 21 Homerton High Street Limited | London | 2017 |
| 21 Hove Park Villas Company Limited | Hove | 2010 |
| 21 Hoyle Road (Freehold) Limited | Redhill | 2007 |
| 21 Huntingdon Street Management Limited | London | 2000 |
| 21 Hyde Park Square Limited | London | 1988 |
| 21 Islingword Road Freehold Limited | Brighton | 2023 |
| 21 Jevington Gardens Limited | Eastbourne | 1992 |
| 21 Julian Road Management Company Ltd | Bristol | 1987 |
| 21 Junction Road Management Company Limited | Wokingham | 2021 |
| 21 Kensington Court Management Limited | London | 1981 |
| 21 Keswick Road Managements Limited | London | 1989 |
| 21 Kingsnorth Gardens Folkestone (Management) RTM Company Limited | Folkestone | 2004 |
| 21 Lady Somerset Road Freehold Limited | London | 2018 |
| 21 Laitwood Road RTM Company Limited | Balham | 2025 |
| 21 Lambolle Road Management Company Limited | | 1998 |
| 21 Lansdown Crescent (Cheltenham) Limited | Cheltenham | 1988 |
| 21 Lansdowne Place Limited | Brighton | 2025 |
| 21 Limes Grove Management Company Limited | New Eltham | 1985 |
| 21 Linton Rise Limited | Birmingham | 2025 |
| 21 Linton Road (Hastings) RTM Company Limited | Hastings | 2024 |
| 21 London Road RTM Company Limited | Broadstairs | 2021 |
| 21 Lorna Road (Hove) Limited | Hove | 2022 |
| 21 Mabley Street Company Limited | London | 2023 |
| 21 Malwood Road Freehold Limited | London | 2025 |
| 21 Malwood Road RTM Company Limited | London | 2021 |
| 21 Management Ltd | Newcastle Upon Tyne | 2025 |
| 21 Manresa Limited | London | 2004 |
| 21 Manville Road Flat Management Company Limited | Guisborough | 1990 |
| 21 Marlborough Buildings Bath (Management) Limited | Bath | 1995 |
| 21 Maury Road Limited | London | 2012 |
| 21 Mayflower Road Ltd | London | 2025 |
| 21 Meadow Close Ltd | St Albans | 2022 |
| 21 Medina Villas Hove Ltd | Hove | 2012 |
| 21 Meyrick Park Crescent Management Limited | Poole | 1996 |
| 21 Milton Road Limited | Cambridge | 2017 |
| 21 Milton Road Management Company Limited | London | 2006 |
| 21 Minster Road Management Company Limited | London | 1993 |
| 21 Montagu Square Limited | | 1979 |
| 21 Montrose Avenue Bristol Limited | Bristol | 1981 |
| 21 Moorhouse Road Management Company Limited | London | 1995 |
| 21 Moring Road Limited | Borehamwood | 1999 |
| 21 Moyers Road RTM Company Limited | Loughton | 2023 |
| 21 Nassington Road Limited | London | 1991 |
| 21 Nevern Place Residents Association Limited | Putney Bridge Road | 1984 |
| 21 North END Road (Management) Limited | Barnet | 1995 |
| 21 Northbourne Road Management Company Limited | London | 2011 |
| 21 Norton Road Hove RTM Company Limited | Wisbech | 2023 |
| 21 Old Lansdowne Road, Didsbury (Flats) Management Co Limited | Stockport | 2020 |
| 21 Oliver Grove RTM Company Limited | London | 2013 |
| 21 Ombersley Management Limited | Bristol | 2021 |
| 21 Overstone Road Limited | London | 2016 |
| 21 Ovington Square Limited | | 2000 |
| 21 Palmeira Square Management Limited | St. Leonards-On-Sea | 2004 |
| 21 Park Avenue South Harpenden Management Limited | Hertfordshire | 1989 |
| 21 Park Road Freehold Limited | London | 2006 |
| 21 Park Road Limited | Croydon | 2018 |
| 21 Parsons Green Lane Ltd. | West Sussex | 1986 |
| 21 Pembroke RD Residents Limited | Bristol | 1999 |