A couple of years ago I contacted the University of Glasgow to inquire about an Army and Navy boxlock which turned out to have been manufactured and sold in 1898. Their response to my email, after about 2 months, gave the dates of manufacture and sale and the name of the purchaser. They didn't give the maker, just stating that "The records state that this is an Anson and Deeley type Hammerless Shotgun." They attached photographs of the record book entry. They did not require payment for their research but did suggest a donation of 40 pounds, which I sent.
The email address to which I sent my inquiry is library-asc@glasgow.ac.uk
This link is to a page on their website containing some advice for what details to include with a firearm inquiry:
https://www.gla.ac.uk/media/Media_803949_smxx.pdf