Ring finals should not be overlooked just because they cost more, are a pain in the arse to install (sometimes) or involve more testing.
chiplard: I agree with what you're saying and think that the ring final circuit has been tried and tested for nearly 70 years now, so why change what is in effect a very satisfactory means of providing multiples of socket outlets to the householder at a very cheap price and with efficiency properties that the humble radial can't provide. The only part of your input about ring finals costing more is wrong though, due to the nature of the ring final it is possible to run in effect an unlimited amount of sockets (taking into account diversity), with half the size of conductor csa compared with the radial which according to cable calcs can only provide a finite amount of sockets and is usually double the conductor csa of a ring final circuit. IMO if it's not broke don't change it, the same can be said for EEBADS as opposed to just ADS with RCD protection!