Not a clue how this one went un-noted, but thanks to Peter Atkinson who has just messaged the site's Facebook account with this update:

Ashington Driver Trainer 8212 (L502TKA) has left Arriva North East and is now in service with Arriva Yorkshire.
It arrived during April 2013 - and looks very nice in her new livery...
http://www.flickr.com/photos/mjs_bus_pics/8851115521/

I've removed this record from the Arriva North East fleetlist.