(31 Dec 2013, 4:04 pm)Dan wrote Are we talking about Brighton & Hove's 440 (BK10 MGV), which was a former demonstrator vehicle?
That was numbered 9147, and was initially on loan at Washington depot for "Red Arrows" service X1 (as shown here).
Or are we talking about Brighton & Hove's 441 (BG61 SXS), which was used for familiarisation purposes at Chester-le-Street depot on "Angel" service 21, (as shown here)?
Yup, as gtomlinson mentioned initially, it was the one for the 21 he was trying to remember.