You do not say how much training you have done so far, I have just commenced study for the ATPL theory. After I have completed this I intend to do the following with PanAm...
IMC Rating, Multi Rating, CPL/IR, MCC, etc.
It all worked out at a bit over 20K.
Their info. pack was quite informative, they laid out everything that has to be paid for (hidden extras, etc).
There is no problem training through them for the JAA CPL/IR (Multi) as far as I know. If you look on the CAA's website they are listed as approved to conduct this training.
They send you back to the U.K for 2 weeks to complete the IR and sit the test. I have a hunch that they actually send you to Multiflight. Perhaps you should ask Multiflight about this?
I think that if you sent off for the PanAm pack you would find it useful. I used it as a good guide for the steps involved in getting the frozen ATPL, of course Multiflight have an excellent website for this too.
I can also suggest that you have a good rummage on the CAA's website, they list ALL the aproved schools for all the CAA/JAA licences there.
http://www.srg.caa.co.uk/sitemap.asp
I hope I have been of some help...
PPP