Thanks for all the comments, keep them coming because the more experiences I hear the better a decision I can make if I do decide to go for the procedure.

From my reading of PUCCI's comment, the recommendation of Moorfields is because they're a known safe choice as they've had many years experience with this procedure whereas if you pick some random just because their address is Harley Street you might not be getting the best treatment, although as others have said there's some extremely skilled surgeons working in Harley Street and elsewhere as long as you know who to choose.

There's also a couple of positive comments about Optical Express, I'd be too wary using a high street store even if the probability of something going wrong is still extremely small I'd rather go with people who are more experience. Now if Tesco started offering it that'd be a different matter, as long as I could get treble clubcard points on it (most definitely joking there).

Finally CarolynUK's comment shows that even respected institutions like Moorfields can mess up at times although that's unlikely to be the same team that does laser surgery.