Cheers for the responses guys. I'm not even sure I wouls want to sell to him now given his emails to me - even if he offered the asking price. Stupid I know but I just have a bit of dislike to him at the moment!
I have mailed him back to say that his offer of £1400 is too low for the guitar and that I could, if I wanted to, sell the parts seperately and make more than that.
As I said before it's new guitars all the way for me now - can't be doing with this hustling business!
I would not sell to this guy.
If you want the best price for your guitar on ebay you should photograph is in as much detail as possible, including under the pickguard, removing the neck and photographing the end of the neck (to show code on the neck) and neck pocket in the body (inportant for identifying refins), the tuners, the front of the headstock etc. Also weigh the guitar. You should also offer to ship worldwide as 70s Teles are more expensive in the US than they are here now.
This may sound excessive, however there are tons of lash-ups on eBay, and if you want someone to fork out top money for your guitar its only reasonable to give them as much info as possible.
Consider the reverse situation: would you buy a guitar "unseen" on eBay for the amount of cash you are asking for it?
Regarding the "issues" unless the guitar is mint, then I don't really see changed pots as a huge issue (although if it had changed pots it wouldn't be mint!!).
Fender started using 1 M pots in Teles from the end of the 60s, which I think makes a Tele too bright, so changing the pots to 250 K is very common.
Changed pickups as an issue, however this can be reversed, so whilst if they are changed this will reduce the value of the guitar, but be the cost of finding a replacement at most. Equally wrong guard etc.
Irreversible modification are the real devaluers of vintage guitars: routing, refininshes, overspray, extra string trees, locking trems etc.