The guys who delivered it are well versed in such matters and the usual alternatives of doors being taken off and windows removed have already been discounted and so I'm pretty sure my only option is to somehow take the unit apart and then put it back together.Have you tried phoning a local removal company? It is possible they may be able to offer some advice.
I am truly fantastic at taking things apart (normally with a sledgehammer), problem is, I am cr@p at putting it back together whereby 'er indoors is gonna be anywhere near happy and I'm living in a 'nag fee' zone....... it would probably look like a lump of C4 had gone off inside of it by the time I've finished putting it back together.
But thanks anyway Newboy !