c-bert,
For most recreational pilots the JAA IR is not really practical unless you have a great amount of time and money to put aside for the training. Unless you have a real use for it (the need to make business trips around Europe and not be delayed so much by weather for example) then you will find it a costly indulgence. Too costly for most UK PPLs.
It isn't only the extra hours that make the IR more expensive. The exams are far more challenging and are more akin to the ATPL ones than those for the PPL.
One solution that many people use is to get an FAA IR and an N-reg aircraft to go with it. The US qualification (the exam in particular) is a much more practical proposition for most people.
If you use the forum search facility you will find a great deal of discussion of these issues and the pros and cons of the IMC qualification.
There is an organisation which promotes PPL IR flying
here.
By the way - the good news is that you can fly IFR to your heart's content in the UK without going to the trouble of getting an IMC - you just do it in VMC.