| 1203 Properties Limited | Brentford | 2024 |
| 1205 Estates Limited | Wigan | 2018 |
| 1206 Property Ltd | Birmingham | 2023 |
| 1208 Properties Ltd | London | 2024 |
| 1208 Property Management Ltd | Northwich | 2025 |
| 120888 Investments Limited | Pinner | 2024 |
| 120A London Road Ltd | Wheatley | 2023 |
| 120B London Road Ltd | Wheatley | 2023 |
| 121 Alexandra Road Limited | London | 2018 |
| 121 Alma Road Limited | London | 2025 |
| 121 Anderton Park Road Limited | West Midlands | 2002 |
| 121 Ashley Down Road Management Limited | Bristol | 1991 |
| 121 Brigstock Road Development - TMG Ltd | Croydon | 2018 |
| 121 Broadhurst Gardens Management Company Limited | | 1984 |
| 121 Castelnau Management Limited | Moreton-In-Marsh | 2000 |
| 121 Coltman Street Hull Ltd | Barking | 2024 |
| 121 Craven Park Limited | London | 2020 |
| 121 Denmark Hill (Camberwell) RTM Company Limited | Bromley | 2019 |
| 121 Edgware Road Management Company Limited | | 2000 |
| 121 Financial Solutions Ltd | Bishop'S Stortford | 2026 |
| 121 Hammersmith Grove Limited | London | 2012 |
| 121 Harvist Road Limited | | 2003 |
| 121 Homes Limited | Newark | 2024 |
| 121 Housing Limited | Birmingham | 2015 |
| 121 KPR Management Limited | London | 2021 |
| 121 Lark Lane Ltd | Liverpool | 2018 |
| 121 Maple Leaf Business Park Ltd | Higham Ferrers | 2021 |
| 121 Newbridge Road Flats Management Limited | Bath | 1987 |
| 121 Properties Group Ltd | London | 2024 |
| 121 Property Group Ltd | Cheadle | 2023 |
| 121 Property Investment Ltd | Dundee | 2020 |
| 121 Property Ltd | Perranporth | 2024 |
| 121 Property Solutions SW Ltd | Cardiff | 2023 |
| 121 ST George's Square Limited | London | 2005 |
| 121 Taunton Road Limited | Bracknell | 2024 |
| 121 Wemborough House Limited | London | 2025 |
| 121 Wemborough Road Limited | London | 2020 |
| 121 Whiteway Road Management Limited | Bristol | 2014 |
| 121-123 Replingham Freehold Ltd | London | 2021 |
| 121-123 Station Road Hendon (Management) Limited | London | 2008 |
| 121-126 Elmhurst Mansions RTM Company Limited | London | 2013 |
| 121.RENT Ltd | Milton Keynes | 2022 |
| 1210 Properties Ltd | Yeovil | 2025 |
| 1211 Bramham Ltd | Colchester | 2015 |
| 1212 Estates Limited | London | 2026 |
| 1213 Louvaine Road Limited | London | 2022 |
| 1213 North ST Guildford (Freeholdco) Limited | Shirebrook | 2025 |
| 1215 Group Ltd | West Bromwich | 2025 |
| 1215 Heritage Homes Limited | Norwich | 2015 |
| 1215 NG Ltd | Leicester | 2015 |
| 1216 Property Limited | Glasgow | 2025 |
| 12165945 Limited | Uxbridge | 2019 |
| 1218 Estates Limited | Horsham | 2018 |
| 1219 Housing Limited | Stourbridge | 2023 |
| 121B Hamilton Road Limited | Colindale | 2025 |
| 121E143LH Ltd | London | 2026 |
| 121GP Limited | London | 2021 |
| 121ROOMS Ltd | London | 2019 |
| 122 & 124 Holmleigh Road RTM Company Limited | London | 2008 |
| 122 - 124 Vassall Road Limited | | 2008 |
| 122 Acton Lane Company Limited | London | 2012 |
| 122 Boundary Road Ltd | Ilford | 2021 |
| 122 Brondesbury Road Management Limited | London | 2001 |
| 122 Ccns Freehold Limited | Barnet | 2025 |
| 122 Chartridge Lane Management Limited | Amersham | 2005 |
| 122 Christchurch Road Property Ltd | London | 2016 |
| 122 Cotswold Gardens Management Ltd | London | 2022 |
| 122 Finborough Road Management Limited | London | 2004 |
| 122 Foord Road Ltd | Dover | 2023 |
| 122 Henry Street Ltd | Ingatestone | 2018 |
| 122 Lexham Gardens Management Company Limited | London | 1999 |
| 122 Limited | Harrow | 2007 |
| 122 Lordship Road Freehold Limited | London | 2016 |
| 122 LR Limited | London | 2017 |
| 122 Maple Leaf Business Park Ltd | Higham Ferrers | 2021 |
| 122 Muswell Hill Road Limited | Edgware | 2010 |
| 122 Old Hall Street Limited | Sutton Coldfield | 2016 |
| 122 the Tower SW8 Limited | Woodford Green | 2014 |
| 122 Upper Grosvenor Road Limited | Tunbridge Wells | 2022 |
| 1221 Capital Ltd | Stanmore | 2024 |
| 1227 Investments Ltd | London | 2016 |
| 1227 North Limited | Borehamwood | 2021 |
| 1228PROPERTIES Ltd | Sheffield | 2024 |
| 123 Antill Road Limited | | 2007 |
| 123 Bayford Road Limited | Haywards Heath | 2026 |
| 123 Bridge Lane Ltd | Bolton | 2023 |
| 123 Buckingham Palace Road Tenant Limited | London | 2018 |
| 123 Cannon Street Limited | London | 2023 |
| 123 Castle Hill Ltd. | Reading | 2007 |
| 123 Clarendon Road Limited | London | 2015 |
| 123 Cleaners Limited | London | 1996 |
| 123 Clydach Road Ltd | Swansea | 2026 |
| 123 Coldershaw Road Freehold Ltd | London | 2016 |
| 123 Drakefell Road Limited | London | 2008 |
| 123 Gloucester Avenue (Management) Limited | London | 2015 |
| 123 Gloucester Terrace London W 2 Limited | London | 2001 |
| 123 Golden Lane Ltd | London | 2023 |
| 123 Highbury New Park Management Limited | | 1999 |
| 123 Home Sales Group Ltd | Manchester | 2025 |
| 123 Home Sales Limited | Liversedge | 2013 |