I have a guitar signed (not by Brian) in a similar place and its a nightmare if you wanna play it as its right by where your arm/hand would be, so the signature can rub off. I had to have mine protected with a clear layer of strong industrial sticky back plastic at a professional guitar workshop to make sure I didn't damage the signature! So bare that in mind if your going to buy it and play it.
WOW thats a beauty, gonna mail him and ask him if he accepts them gold british arcade tokens. surely you could just buy a burns red special for £500 then take it to a show and get it signed for free, or is that a fat chance that probly wouldnt happen.