Following my post from yesterday, I collected the tools and prepared to have a look inside the brake drum.
Quite a lot of dust but no real damage. I started the centralising again, carefully following the instructions and it seems that all is well.
Presumably I did not follow the instructions properly last time.
The only thing that I noticed that looked odd was that the eccentrics were set to open the shoes out to nearly maximum, which is not the case now, nor what you would expect with new brake shoes.
I guess that my last effort was just a c**k up.
“Could do better” as I seem to remember hearing a few times in my youth.
Roger_G