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What a pity: it’s a pretty guitar. Bad luck for someone
Your location shown as London, which won't help. You could probably find a luthier outside of London who would be 20% cheaper than someone good in London.
I guess it also depends on how good you want the cosmetics to look afterwards. If you aren't worrying about touching up afterwards and hiding the work, it might be a bit cheaper. That will affect resale though. Resale will be bad anyway if you are being honest about the guitar's history. Unless you are certain it's one that you will keep long term, you would be better off buying a clean one as you will get the extra back when you sell it on.
The other alternative is to offer £250 for it. That would give you more leeway in terms of the repair cost. The worst that can happen is that the seller says no.