Thanks GW. It definitely appeared to be slightly looser on the side stand, not tighter, but will recheck it tomorrow as have a long ride on a Tuesday.
It may be that I'm in the habit of pulling the bike backwards by the grabrail when it's on the side stand to stop it rolling off, so may have extended the suspension again.
Can I assume by middle of the run you mean the centre of the distance between the sprocket centres, or the centre of the visible lower chain run?