LOL!
I had another problem though, trying to fit snowploughs to my 47200.
Managed to dismantle the sprung buffer arrangement and fit the ploughs, but there was no clearance between bogie and snowplough. It seems the chassis is slightly different on the sprung buffer variants.
After much faffing about, I simply swapped the chassis over with an older model, fitted the ploughs to that and things now run as they should!
I never got the sprung buffers back together though, so they're now glued solid!