I understand from Simon Spare that his GC cattle wagon kits are more or less ready to go out. Cost £25 each plus post with a choice of grease or oil axleboxes.
Both fitted and unfitted versions originally had grease boxes but they would have slowly been upgraded, especially the fitted ones. Don't ask me exactly when.
There's a photo on the GCRS Yahoo website and they look to be another excellent product.
Please note for these wagons you will need 'GCR' and 'number' plates NOT the usual lettering. Now how shall we procure those??? Photos of these wagons in GC days (to show you what I mean) are quite rare. There is a partial on p 73 of Locomotives of the Great Central Railway, volume 2, by E.M. Johnson, that shows enough if you look at it carefully.