I replaced these bushes last October, and had the same trouble getting the bolt out. See thread below:
https://the75andztclub.co.uk/forum/s...d.php?t=289183 &
https://www.the75andztclub.co.uk/for...d.php?t=288802
My bolt was badly rusted and wouldn't undo. I was lucky enough to borrow a long 18 mm snap-on ring spanner which I found was easier to manipulate back and forth, whilst giving the extra leverage needed. Try doing up the stubborn bolt just a fraction and getting it to move back and forth.
Be careful not to get injured, smashed knuckles and fingers etc shoulders can get strained. I somehow pulled a muscle in my hip which took about 6 weeks to stop aching
