Hi Jude
Have a word with the guys down at Flightpass, Exeter,
www.flightpass.co.uk .
I recently renewed my IR with them, on recommendation from a mate of mine, and they were excellent.
It's all done on their FNPT II, configured as a Seneca III, and it's very realistic. The package they offer is up to 1.5 hours practice, and the duration of the test, again, up to 1.5 hours for £290.00. You pay direct to the Examiner his fee of £160.00. If you need any more practice time their rate is £145.00 per hour with first class instruction.
Considering the expense with renewing on an aircraft, I felt that this was great value for money.
Hope this helps, and good luck
D 'n' H