Depends where you are and if you have time.
Camden Market is worth a visit, Daves stall and monkeys emporium
But if you are slap bang in the middle near Covent Garden then Orbital Comics sometimes have a handful of loose figures
and the cinema store 30 seconds away from orbital had two way overpriced carded potf cards and a couple of loosies
Also mimi fifi in notting hill had a shoebox of loosies last time I was there
let us know how you get on
Collecting vintage loose figures, ships and playsets since 1982.