try a neighbouring city/town outside London. When I was residing there, I recall prices were very high anywhere around Greater London and most of the ones I tried, even many miles outside Westminster were not that much cheaper either, where most of them claimed that they needed to be sent away. Sometimes cheaper isn't always better, so I would personally look around some of the other neighbouring cities that have independent watchmakers and most importantly, I would prefer that the person that you speak to is the one who is doing the job. Good Luck!!!!