Yes, the ring circuit is found in practically every house in Britain. Even though the ring has been in use over 50 years now, the IEE Regs. have always kept radial circuits in as alternative arrangements, although the allowable number of outlets, floor area served per circuit etc. have changed regularly.
I haven't sat down and worked out the price difference, but as far as new construction is concerned, I don't think it would make much difference. 2.5mm twin-&-earth cable runs about £15 per 100m drum, typical domestic type-B MCBs about £4 to £5 each. Extra labor is just going to be pulling a few extra cable runs, which on a new building is easy. Compared to the overall costs of £2000 upward, any extra cost would be negligible.
