Don’t know if you can locate one but I’d suggest a Browning Auto-5. Find one made in Belgium.
It is often referred to as “the humpback.” One look and you’ll understand.
Good luck.
Owning an A5 in the UK can be problematic, one fellow on the Browning forum at Shotgun World said the magazine tube needs to be crimped to only allow 3 shots, which given the long recoil system might be a reliability killer.