the original selling price was around £650, more recently this went up to about £800. It's a good deal, so forget about putting this on at £4.99 and waiting. The cartridge alone is £300, so my advice would be to split the set up and sell, individually, the cartridge and the t/t.
Depends what you paid, what you want, etc., as well as how much you are happy for Ebay/Paypal to whip off you in fees (which won't be chicken feed incidentally).
If you already have an account with them, try hififorsale's website (I hear there's been issues for new members signing up to sell, but existing members are apparently okay). Failing that, stick it on gumtree and also the Hi-Fi world classifieds too which are free.