The rear is now fitted!
I'd psyched myself up to expect problems getting the bottom bolt out, and even
more problems getting the bottom bush out. I needn't have worried. I wedged a piece of wood under the rear tyre so the swingarm didn't drop. As advised elsewhere, I got some heat into the bolt, to soften the threadlock.....I used my wife's hairdryer - its quite a powerful one!

Under the swingarm,there's a slight bulge which is the threaded, blind hole that the bottom bolt screws into. I played the hairdryer over that area for a good 6 or 7 minutes, the bolt came out easily just using a standard ratchet handle, no need for breaker bars or other heavy-duty assistance that I'd read about elsewhere. Next was the bush - again, no problem. I put a wooden dowel onto one side of it, bit of a tap with a hammer, it slid out nice and easily - it comes out on the same side as the bolt does. The top bolt was a piece of cake. No other dismantling needed, just a bit of wiggling to get the unit past the mudguard.
Replacement was just a little bit more complicated than I expected....but only a tiny bit! The top mounting for the unit sits between two frame tubes

- rsz_wp_20171215_002.jpg (270.69 KiB) Viewed 8799 times
The welds that I've highlighted can have very slight variations in thickness from bike to bike - mine would appear to be of the fractionally
thicker type! This meant that the top mount on the shock wouldn't fit through the gap!

A quick call to Mike Capon (Shock Factory owner) soon had me sorted. He's come across the issue on very, very few bikes (lucky me, eh!), but advised me to remove a tiny amount of metal from either the welds or the top of the shock around the eye for the bolt, using a hand file. I chose the latter, aluminium being easier to file than steel - and you can't see it when its done anyway. Mike assured me that this would have absolutely no effect on the strength of the top mounting, which was good to hear! It didn't even take 2 minutes of filing, such was the tiny amount of metal that had to be removed to give sufficient clearance.
Once that was done, top bolt in, new nut fitted. Bottom bush cleaned up, copaslip applied, new bolt (came with threadlock already applied) went straight in. Everything torqued up (2-stage on the bottom bolt, why do they spec it like that?), job done!
All I need now is a 15-degree increase in ambient temperature and I can try it out!
Pete