Once they get a belt they don’t leave UK and fight bums, it’s also VERY hard for people to win a decision over there.
not really, there are some of those like Terry Flanagan but it's not the common nowadays
staying in the UK and fighting bums?
let's see their current champions
Joshua: fought only in the UK so far but not bums, he has the best HW resume now
Groves: Dude fought damn near everyone who worth a note in that division the last few years
BJS: tended to fukk around in the past, still not what you would call "stay hom, fighting bums", he recently went to Canada
Lee Selby: he is the one who maybe belong in your category dude really didn't step it up since he won that belt, thankfully he's about to do so finally
Kal Yafai: Well, he only had 2 fights since he got the belt, not the worst calibre of opponents but also not the cream of his division
other relevant British champions from the past few years...
Frampton: fought LSC twice when he had the belt, once in the US
Brook: fought some light opponents but then fought GGG and Spence
Khan: fought everywhere with some quality opponents
DeGale: fought in the US/Canada multiple times, against Jack too
Terry Falnagan: your definition is probably the most true to him
Liam Smith: meh, but he still went to fight Canelo, it's a big money fight so there's that but still, you can't say he stayed at home and fought bums for years long
Haye: went to Germay to fight Klitschko
I'd also mention Eubank who's not a champion yet but he also seems to be down to fight anywehere with anyone
So your definition is only true about the small minority of recent or current British title holders, it's over the times when UK fighters were only hiding their belts at home, fighting bums