(03 Jan 2023, 4:10 pm)Storx wrote Had a little look there and it seems they've had the following:

Leyland Olympian Northern Counties
Arriva - https://www.flickr.com/photos/emdjt42/4277604294
Go North East - https://www.flickr.com/photos/emdjt42/3774409751
Stagecoach - https://www.flickr.com/photos/27204054@N07/3182722012

Dennis Dart SLF Pointer 2
Arriva - https://www.flickr.com/photos/adammalarkey/15616194284 (S***KHN / X***GGO)
GoNorthEast - https://www.flickr.com/photos/emdjt42/5064713021
Stagecoach - Still In Service

ALX300 - B10BLE
Arriva - https://commons.wikimedia.org/wiki/File:..._pic_1.jpg
GoNorthEast - https://www.flickr.com/photos/27204054@N07/3266874278
Stagecoach - https://www.flickr.com/photos/williamsonm/6258924570

You're right on the Olympians though, similar with the original Darts - Arriva inherited some with Darlington seems like GoNorthEast had already disposed of theirs by then though.

I forgot about some of them! Especially the random Alx200 that GNE had and the Darts at Belmont. 

Genuinely thought SNE had got rid of their Northern Counties Olys by then too.