I have seen pictures of 49 on a lo-loader going to Cosford, definately looks Air Defence blue or as near as dulux could get it.
As per Sir GC's link, the final Nimrod colours were, i think, camouflage grey, or is it barley grey? Certainly not even remotely blue...
Photos: Hawker Siddeley Nimrod R1 (801) Aircraft Pictures | Airliners.net
-RP