I think I will stick to asking questions instead of trying to answer them :)
Spink 2014 values this coin at £1200, which really surprises me!
A dealer, as standard would probably offer you 50% ish of what he would sell it on for. So I'd expect them to offer you a maximum of £600 but probably less.
On
ebay, it appears they sell for anything between £700 - £1000, so again I would advise that
ebay is your best option, if you can be patient, put it on for £1200 or nearest offer and see what happens, then if no interest, drop it to 1k or nearest offer.
If you want to be selling quicker, I would list it on
ebay on 7 or 10 day auction starting at 99p, put as much info in as you can find, including Spinks valuation. I would think you will net at least £700 after fees.
I personally wouldn't spend £600 on this myself, so I cannot help :(
Again, I would highlight the spink valuation, as I had a quick look on 'coins of the UK' and this values it at just £350, and others may do the same.
Hope my final answer helps :)