Job done! I used a succession of extensions with wobble ends to get the access nececerry. The retaining bolts were rather stiff to undo and had to be wound out all the way and I couldnt get enough purchase with shorter extensions and the stubby drive

Not a good job to do outside in the cold though! You need to be able to see with your fingertips to get the bolts back in and numb fingers are not terribly good at this...