Re: 1987 RG750 - advice please
These don't pop up for sale too often (RG750 that is), not in great condition anyway.
I would not really like to say definitively as the price for second hand Ibanez guitars of recent has become somewhat of a guessing game.
In my experience over say the last five years or so I have seen a mint ruby red go for £400 (still wishing I had pressed the trigger faster on that), seen a white one/not mint go (cant remember exactly how much to be honest) for around £550 & a year ago or so was talking to a bloke selling an excellent condition ruby red who was asking for £600 (I believe it could have actually been the one I missed ..lol). So really down to what you ae wanting for it and what the buyer is willing to pay for it. So in all honesty you could potentially sell for above £650 depending on the condition.
Just looking on certain auction sites will give you an idea, if you look at models Like obviously RG750, 760 & 770 you will get a feeling for what people are asking. Although these prices do seen to be inflated by buyers that then sell on at higher prices - an example of that would be looking at the current prices for the second hand RG770's available most of which have been available.
Where in the UK are you? What condition is the guitar in?
For total transparency here - As a player/collector Yes I could be interested in your guitar should you decide to sell.
All the best