According to "Encyclopedia of British and American Tanks of WW2"by Chamberlain & Ellis, here are the British designations:
Grant 1 = M3 with turret to meet British specifications, no cupola, (turret rear extended to house radio)(As Tamiya 'Grant' kit)
Grant II = M3A5 with original US turret. (M3A5 had diesel engines and therefore can't be made from the Tamiya kit without modification)
Lee 1 = Standard US model (the Tamiya kit is supposed to represent this version)
Lee II = M3A1 (cast hull)
Lee III = none delivered
Lee IV = M3A3 ( Continental diesel engines, welded hull)
Lee V = as Lee IV but GM diesels
Lee VI = M3A4 (Chrysler engine)
There were others as well such as ARVs, command tanks and Scorpion nine clearance vehicles.
Most British Lee/Grants were used in North Africa, and when replaced by the Sherman were sent on to Burma. Some where also sent to Australia, but I don't know how many and of which types.
I don't know which units used them, but colours in North Africa would be light stone no61. sometimes with silver grey no28, slate no34, or terra cotta no44 overpainting. Colours in Burma would be jungle green no13 or deep bronze green no16.
Tamiya colours Buff, Sky Grey, Field Grey + white in about 1-1 mix, and Red Brown are about the best matches for North Africa, and Olive Green for Burma. (my opinions on the colours, others will probably dissagree!!)
Hope this is useful.