Bingo, This could be your lucky day! I have a very good friend up in County Fermanagh who has zillions of Ps. annulatus Guinee.
If you go about it in the right manner I'm sure he will send you some. The cost is between you and him. Let me know what you decide.
Regards
BigC
PS. Your only problem here is that I know for a fact he uses rainwater and they seem to love it. So you would seriously need to make arrangements for testing his water and try to match it or alternatively aclimatise the fish very very slowly. In either case you would be best trying to match it or at least get close if you wish to spawn them for future generations.
Let me know and I'll speak to him first and send you his email address whereby you can contact him direct.
Always glad to help a Yorkshire man. (Lived in Bradford for many a year, still have many good aquarist friends there)
Try joining a local aquarist society, I think Halifax A.S. is still going, honestly speaking these are the places to source almost any fish not to mention the knowledge you will gleam from members and contacts. Joining Bradford and District A.S. back in the early eightys was the single most influential thing I ever done in my time in the hobby.
Halifax Aquarist Society Mr D Fryer Tel 01274 880471