Don't Give up hope ColinH! A mate of mine had an Ibanez Roadster (guitar) stolen at a gig in the mid 80's.
He saw one uncannily like it for sale on ebay in 2012, also it was in our old hometown in the North-East. (he now lives near Glasgow)
He contacted the seller, who trotted out a story of how he'd owned it since new, but had given up playing in the early 90's,
and couldn't bear to part with it, and it had remained in it's case under the bed for the last 20 years.
My mate asked him if he could tell him the serial number, so he could verify it's age. Bingo! Same serial number.
He then asked if he could arrange a day to go and try it out, he went (receipt in pocket) Played the guitar for around 20 mins or so,
put it back in it's case, picked it up, showed the guy the receipt as he told him that he was taking the guitar which was rightfully his back.
I know this don't help you personally, but it proves things can turn up! I wish you all the luck in your search!