About Single Phase Generators
Almost all generators sold for domestic, camping and light trade use in the UK are single phase. They typically deliver power through 13A 3-pin sockets and 16A 'Commando' (Ceeform) blue sockets.
Single phase generators are available from 800W up to around 12,000W. Beyond that, you generally need a three-phase generator — though three-phase units can usually deliver single-phase output too.
Choose your size by adding up the running watts of everything you want to run at once, then adding 20–30% headroom for motor start-up surges (fridges, pumps, compressors).