Years ago I purchased a signed copy of Game of Thrones - A Dance with Dragons from Ebay.
It was an impulse buy while being much younger and naive to finding out how to authenticate items... Now years later, I am having worries about if it is the genuine thing.
Due to the simplistic nature of the signature and lack of fine detail, it's a tough autograph to authenticate. That said, this looks likely to be ok.
It is consistent with the signatures I have received in signed books directly from Martin.
Thank you for your help, I have been trying to compare it to other signatures online but without knowing what is a real / fake... It is hard.