I think you'll find that the one based at RAF Mildenhall is actually USAF, not RAF. The USAF's U2s usually carried minimal markings (and even spurious ones, to throw off potential Soviet spies) during the Cold War.
When once you have tasted flight you will walk the Earth with your eyes turned skyward.
For there you have been, and there you will always long to return.
-Leonardo Da Vinci