stuck in 2nd

Finally had chance to have another look at it. I disconnected all the shift linkages from the side of the block. I think the 3-4 and reverse selectors are in neutral but can't be 100% sure. Anyway I can't move them or the 1-2 selector from the postions they are in - they aren't seized solid but they won't move enough to engage or disengage the gears.

The shifter moves perfectly through all gear positions when disconnected from the transmission.

Guess I'm just going to have to take the side cover off this weekend...