I've done the JAR IR distance-learning ground study course with Atlantic. We had two brush-up courses, each for 1 week at Coventry, before sitting each exam module at Gatwick. The standard of tuition during the in-house brush-up courses was first rate. I was the only IR student (although the ATPL courses were well attended) so I had the luxury of one-to-one tuition from my tutor! The back-up during the home study part was excellent, and I found the tutors highly knowledgeable and pleasant to deal with at all times. Another real bonus was watching Douglas DC6's and DC3's and Lockheed Electras trundle past the window at Coventry!! You also get to study Boeing 737 systems using Boeing's CBT training software. You will need this as around 30 per cent of the questions on the Navigation and a fair number of questions on the Instruments paper required quite detailed knowledge of EFIS use and interpretation.
Having said that, the JAR IR option (as opposed to ATPL) obviously only appeals to a tiny number of aviators. For each of the exams at Gatwick, I was either the only candidate or one of two candidates. For most people, the ATPL course makes more sense (total of 14 exams). If you aren't considering a commercial career in a JAR country, the FAA route makes more sense for a private pilot - you just need an N-reg, aircraft to fly when you get back to the UK.