You said you needed a map based in the UK? (You may need a few map devs, I'm learning how to use hammer -- May be a long process but it will be worth it).
(Recommendations, not my maps)
gm_Shambles (Night):
https://steamcommunity.com/sharedfiles/filedetails/?id=151544081&searchtext=Gm-Shambles
Features (Night Version):
-10 houses with interiors and gardens
-English architecture -based on my real street
-Fully noded environment
-Optimisation for intense gameplay
-Big build space
-Huge farmland
-Sewer system
-HDR lighting and seamless 3D skybox
-Custom sound for creep factor
Requirements:
None
gm_Shambles (Day):
https://steamcommunity.com/sharedfiles/filedetails/?id=191110821&searchtext=Gm-Shambles
Features:
-New day lighting
-10 houses to explore
-English architecture
-Farmland
-Sewer system
-Massive skybox
-Fully noded environment
-Cube maps, HDR lighting
-Ambient sounds
-Balance of space, detail and atmosphere
-Optimisation for intense gameplay
Requirements:
None