For 80 pounds I'd do it myself honestly, it's not a complex job if you know what you're doing, then again I dabble with DIY watchmaking.

What type of crystal does your watch have ? Is it hardlex/mineral crystal ? That one's as cheap as 10 pounds or so... You can get a press for another 20... Just saying... But I'm not advising if you don't know what you're doing as bad things might happen.

There are also homemade pressure tests that can be done. I think I remember someone using some bottles and tubes or something like that...