EGDR
You'd need to pass the examinations for CPL which include the IR exams. Cost about 200 Sterling if you pass them all first go. Prep and check ride for CPL and MEIR in the region of 1200 Sterling if you're already rated multi engine. If not add another 400 Pounds. With the exchange rate being what it is you could probably slip enough change from that for your medical. Accomodation would have to be arranged but the bloke who runs the school has a large house with pool and barbecue area about 5 minutes from the airport. He usually puts students up at his place. Just hope you're not vegetarian and teetotal.
There's also a possibility you can validate your JAA licence by writing the Air Law and Procedures examination, getting a medical and doing a check ride with an examiner. Rough estimate around 700 Pounds.
Good luck...