Hi Mick,
PSS are generally either home made, or modified kits.
Some RTF planes (on top of my head, I think of the Ripmax Spitfire and the little ME109 from HK that John have) do pretty decent PSS models.
After that, you go EPP. Miniplumes do a lot of them, and they are all great flyers:
http://miniplumes.eleotech.fr/crbst_5.htmlA bit more work than a RTF thingy, but durable and design to be PSS models.
You also have a few links at the bottom of this page:
http://gliderireland.net/index.php/pss-in-irelandAnd of course, if not done already, browse the PSS section of the forum for some good ideas