Thank you for the very detailed response John, I really appreciate you took the time to do that, this is what I found:
The action is pretty low already, if I take out the hardwood shim under the saddle I get buzz.
I had to look up truss rod adjustment, ...while fretting at the 1st and 15th, the gap between the strings and the 7th fret looks to be about 2mm on both the top and bottom E, the neck has a slight bow as described in the article I read so I don't think that's the problem. In any case I'd best leave that to the experts!
Saddle is nice and snug and there are no grooves in it.
I couldn't see any fret standing higher but other than looking at the gap below the strings I don't know how to check this.
Technique, I don't think it's that either because the string goes flat (not sharp) as I go up the neck, when it happens I can bend the string into tune.
The strings are about 2 months old, Adagio pro medium guage, they're not too old but they were cheap. I can give this a try - is there a recommended type for Avalons?
Looks like I'll have to find a local luthier!!
Thanks again John