Exotic Avro Yorks?

I’ve been searching for unusual paint/markings schemes for Avro Yorks and I came across a picture (Aeroplane Monthly July 2006) of MW234 taken in 1956 at Hucknall. The aircraft appears to have been operated by A&AEE at the time and wears a standard silver finish but with a white fuselage top and what appears to be white paint also applied to the upper portions of the fins, together with what I assume to be a blue cheat line.

Anyone know more about this scheme? Is it a blue cheat line? I also wonder if the wing upper surfaces were white too?

If anyone knows of any other shots of this aircraft I’d appreciate any pointers. Thanks!