2litre petrol manual, pre facelift.

I have the servo out, new one in but for the life of I can't get one nut onto it's threads - this is one of the 3 nuts that retain the servo to the bulkhead, in the footwell.

The bottom and right nuts I can get on fine but the top left nut is an absolute b1tch to get started onto the threads.  The problem is access, not only is the pedal box an awkward place to work with the dash in place but there is 2 metal flanges (part of the housing / brackets for both the brake pedal and clutch pedal mounting points) that prtroud about 4 inches from the bulkhead and there is about 3 inches between them to fit this nut onto the servo bolt.

Way too small to get a hand into and really awkward to get an extension / knuckle joint square enough to turn the nut onto the threads.....

Not sure if any of this is making sense but if anyone has done this before can they tell me how on earth they got this nut on??