Max, old fruit, fear not. I was in exactly the same situation as yourself but a call to the CAA revealed that there was a slight mistake in the AIC in question and your rating (i.e. JAR rating issued before 1 Jan 2000) is in fact valid for 25 months. I think Tim Denyer is the man to speak to, good chap and very helpful. The revalidation criteria remain the same but you have 2 years to meet them. Ratings issued after 1 Jan 2000 have 3 year validity.
Meeb, Watford will know that one if he's around.