Hi Andrew,
Have done a fair bit over that way in the past and may well be visiting the area again in September if not before. Access to some of the systems can be somewhat delicate so I am reticent to post too much info on a public forum such as this. If you let me know how far from Perpignan you would be looking to travel and which, if any, caves you already know something about I can send you a PM with extra info as required.
Cheers,
Nig
p.s. It's good to see the CPC (used to be a member myself) getting farther afield than Horton in Ribblesdale!