Time of year can affect sale (not just price), people starting to think about Christmas etc.
I think your car is worth the money, but don't think you would get a sale at £7450 in todays market.
Advertised at £6750 you would get a few calls I suspect, with people coming to see it and offering around £6250-£6500. I know a big drop, just think buyers market for mk5 GTis at the moment.
Plus all depends on how quickly you are keen to sell. Advertising cost, running coats, depreciation etc all come into play after advertising a car for a long time.
Good luck with the sale.
Si