I always find looking for Flats a bit of a mystery tour. The websites are generally very confusing and unprofessional, for example inability to search by size? I'm not interested in 30mm so wading through endless pages looking for larger sizes is tedious to say the least.
In mitigation maybe the sheer size of the market in these things makes on line listing difficult.?
I get the impression it is very much a cottage industry.
Keith