Thanks for those John, I said it would all change didn't I.
When I saw the original pic showing the serial on your site I dithered between WH667 and WH887. Chose 887 as you know, wrong choice. WH667 was indeed a 45 Sqd Canberra around the time of Op Firedog.
The source of the nose art changes then. It is in all probability a "zap" by the USAF "Grim Reapers" sqn and was probably put on 667 during one of the many inter-service visits between our FEAF and the US bases? Zaps were abundant back then.
So, scratch the nuke stuff above, these tired old eyes that saw a "mushroom", now see a scythe!
Still intriqued by the T.4 though.
Ah well, 'twas interesting for a while.
