https://www.ebay.co.uk/itm/yamaha-xt600 ... 3853882187

Would you say £5k is a fair price?

Not a chance. 3 tops.

What he said, and then only if the mileage is really that low

This is the bike I posted about several times on the forum, I found a red and white Tenere so I sold this blue one last year for £2k with a spare tank because the original one was in such poor condition. It looks like the guy I sold it to, has sold it on already.

It was roadworthy when I let it go, but the frame is very tatty and there is a load of missing paint and some rust underneath the seat and bodywork.
The tank is dented and badly rusted underneath, the rear rack has a split where it mounts to the frame, the paintwork is generally very poor - the photos do this bike far too much justice.

As far as I can it has not been touched since I sold it - even the handlebar grips are the same level of dirty.
£5k would buy a pristine 3AJ. This one is not worth more than £2k which I think was a fair price for it last year in its condition.

Just goes to show one needs to view eBay bikes before committing to buy.
I bought my XTZ750 off eBay and as the seller was 400 miles away I took a gamble that would be OK when I had it delivered.
Fortunately I got lucky with no nasty surprises but the seller did have 100% positive feedback.

I agree.
I've bought several bikes long distance and sold a few too and I've had no complaints, on eBay and on gumtree.
But, this very Tenere was the first bike in a long time that I had to complain about to the eBay seller - it was a distance sale, I didn't see it before bidding and the true condition was somewhat disguised. I complained, but I kept it and got it MOTd and back on the road.

That said, I paid £2300, which was arguably too much. £4995 for this bike is fanciful at best.
I'm wondering now what the bloke I sold it to, did with the spare tank - the one photographed is the same rust bucket I bought the replacement for.