If she is a relative why didnt she call you in the first place for your advise or is it one of them "i will get him ln on the cheap coz hes only a plasterer?" To be honest mate i would leave her to it and say "you doin the plastering will void the guarantee". If she can get her money back happy days oh and some people keep sayin its a lot of money she has forked out but i cant see how much it was so how much was it?