Hi Scarlett,
The best way to find the appropriate agents is here:
http://www.writersservices.com/agent/uk/agent_uk.htm
But I agree with the others that doind as much honing as you can on your manuscript before submtting will maximise your chances. If an agency rejects the ms, they won't look at it again after it's been polished unless they specficially indicate they'd be interested in looking at a revised ms. So you only get the one chance with each - and I'd guess that with something a bit 'niche' like erotica there's a smaller number of agents in the field than for more mainstream fiction.
Also wondering if the Romantic Novelists Association (which includes a ot of HMB authors, including their 'hotter' lists) caters for writers of erotica as such. Might be worth checking out their site to find out. They charge for membership but are a great place for networking within the broad romance genre, and offer a critiquing service to new authors as part of the benefits of membership.
Best of luck - oh, and welcome to WW!
Rosy