As MM said, U need to sit the CPL (or ATPL) exams before taking the test. This is likely to B the most difficult bit for U, considering U haven't been a "student" for some time.
Your FAA CPL (even if not current) can still get U some training exemptions for the JAR CPL, but your IR is unfortunately "useless" (since February 2001). For the flying part, expect to spend around £4k for the CPL, & £10k for the MEIR. Shop around for the prices, don't pay more than that.
U can indeed take correspondance courses for the ground examinations, but I would not advise a "part time" course for the CPL &/or the IR, as it'll take U forever to achieve the standards. Each of these 2 courses takes 3 to 4 weeks full time (depending on the weather), so it can B done during your holidays.
As for the age issue, I suggest U read
this thread, which might give U some ideas.
MF