Ha, it was 300CE that pointed me in the direction of the replacement vac back in July last year!
Anyway, I remember the reason I couldnt remove it was because I couldnt access the 13mm nut and nearly rounded it trying to get at it with a flexible ratchet spanner. I didnt realise you had to slacken the 10mm to rotate the unit so that the vac was out the way.

Anyhoo, I got it off. And put the replacement vac on.

I messed up marking the position by marking the mounting bracket.

I'm going to replace the felt pad before I put the unit back. Any idea where I would get one?