Best thing is probably to get an up-to-date eye test (they'll want it within 2 years anyway I should think!) and let them know asap!
pugwash, they say they assess individually if you're over 26, but I don't know what that means if you're outside the limits - they may be more restrictive! The official limits from the CAA for the medical are detailed via the links
here but NATS do seem to be more restrictive. (CAA only quote the JAR Class 1
here, though say the CAA Class 1 limits are similar)