Theo wrote:

https://www.ssen.co.uk/ConnectionsIn...EstimatorTool/
gives 'illustrative' prices:

New supply - House/Flat

Urban single phase: £5140
Urban three phase: £9518

Rural single phase: £4017
Rural three phase: £4675

Those are roughly triple WPD's illustrative prices, they don't quote
domestic 3ph, but they do quote small commercial up to 69kW supply (i.e
3ph 100A)

https://www.westernpower.co.uk/connections-landing/get-a-guide-price/interactive-costing-tool