LFF = London Fetish Fair
BBB = Birmingham Bizarre Bazaar

Each runs at least once a month and I believe the events that run during or around these events usually make it worthwhile travelling - there are club nights, munches, fashion shows and demonstrations as well as the trade fair.

There is also Carnival of Souls which I think still runs once a year - ostensibly a goth/metal/industrial music event but some of the traders who attend are suppliers of BDSM equipment as well as there is a definite fetish element to this event.

These are the two largest (that i know of) fetish events in the UK and have stalls where fetish traders show and sell their wares. Some will be traders where most of the stuff is bought in from a supplier but some will be traders who also make thier own stuff for sale. Its the latter you need to.

You sometimes also have traders at smaller events such as play parties and your local munch may have members who are also traders (or at least know where you may find some).