Just noticed you asked about Retzius Sparing too.
There are probably around 5-10 surgeons in the UK who do that.
It is available on the NHS from specific surgeons at Guildford, UCLH, and Reading that I know of. There will be a few more places too that I don't know of I'm sure (probably more of the London hospitals).
Retzius Sparing tends to give faster recovery of continence, often immediate. However, at the 1 year post op point, continence is the same Retzius Sparing or not, as non-Retzius Sparing patients catch up later.