(01 Dec 2016, 5:46 am)Dan wrote As that was the reason it was at Saltmeadows for about two weeks!

Rear body repairs, and having the back painted blue.

3995 is there now for the same treatment, and 6122 has also been for that purpose.

Unless it had to be rushed away...

Guessing it is the bit in bold:

Go North East 6128 / GX03 SVC. by Guy Park-Royal, on Flickr

3983 is still shown as being at Chester-le-Street, too.