I found a video on T'Internet on how to put a bike on a centre stand. Brilliant! http://bikesandtravels.com/biker.aspx?ride=1014
I've always struggled getting a big bike on the stand, and it was getting to the point that I wasn't really lubing the chain properly, so I had to sort it. Google being your friend and all that, I found this video which explains that you don't lift the bike, you push down on the stand as hard as you can. I was sceptical, but it works. That's Physics and levers for you.
and since it has been some months since changing the spark plugs, and the starting problems seem to have faded away (with a small remaining issue with the tap on the petrol tank being blocked except on the reserve tank), I think I can safely say that the spark plugs being wrong were the cause of the starting issues.
Now all I have to do is work out why she is consuming oil at about a litre every 1000 miles - or is that OK for an old girl like this one?