Sounds like you hit that golden age of UK vintage, i used to collect 70's era MiJ Nike runners in 87 so was always aware of the Levi's by trawling the vintage shops but by the time i got around to buying them in 92 (when i couldn't afford to buy new jeans) the golden sizes with a decent inseam were getting hard to come by and/or too expensive...
I had rent to pay and a hectic social life to consider
Used to visit London regular mid 80's to mid 90's, originally looking for old Levi's and mainly 50's styled attire. Would visit all the markets, vintage shops, walk the length of the Kings Rd up to American Classics, Kensington Market, Camden on a Sunday. Decent inseam length was always hard to get. Back then never had the budget for the really old good stuff so ended up with mainly 70's Levi's. Often stayed the weekend as generally there was someone I knew living there so there was a sofa to crash on or if we were lucky a student house party to go to.
The purpose of these trips changed in 1989 from daytime shopping to nightime driving around the M25 Normal service and style was derailed for a couple of years and then settled on a mix of vintage denim, skate & 80's old skool.