Jarvy
Knowing how much you always enjoyed it, and your passion for flying I don't think you should give it up.
However being practical is it a reasonable expectation to get the money together and obtain an IR in a reasonable time frame and get the money back.
How does the medical condition (or lack of now) affect what you used to do for a job ?
Is it worth calling the companies who would need IR co-pilots and asking them direct before you spend the money and then get told no thanks.
I guess you would be looking at a career co-pilot job in JAA land.
I hope it works out for you.
Cheers
Gary S.