NYMR Collett Tender - Which Loco?

[Trainz6013]

Hello everyone, I was recently at the North Yorkshire Moors Railway and noticed a grey-painted GWR Collett tender in the yard, seen in the attached image next to the crane and BR Standard tender. Now I'm curious - which locomotive does this tender belong to? There is no GWR locomotive based at the Moors, and there wasn't one visiting either at the time of my visit.

Does anyone know which locomotive this tender belongs to?
Thanks

 

[Clarence Yard]

It was purchased for use with 3814, which is being restored in Stockton.

 

[Trainz6013]

It was purchased for use with 3814, which is being restored in Stockton.

Thank you very much for that @Clarence Yard ! I had completely forgotten about 3814!