In that part of the world I'd recommend getting in touch with all the local jewelry dealers who take in pre-owned items, both high street and the more obscure, with all the info you have. Fortunately many UK jewelers stay abreast of one another, or at least used to, and word of mouth can be invaluable in such a case, especially if the thief doesn't know what they have and go to someone trying to 'fence' it w/o full knowledge of what it is. If there are any known fences in your area and the theft was reported by the police, they will likely be the first people checked, but pro movers of stolen goods have gotten quite careful these days. Beyond that, you can try to keep an eye on sites like ebay and Chrono24, but that will quickly get arduous.
I am deeply sorry to hear about this, as I lost a favorite Seamaster the same way a few years back, and wish you nothing but the best of luck and its safe return.
