Quilting Cat has it right--when it's your idea to make something for someone, that is a gift. When it's requested, then it isn't--no matter how well you might know them! When people ask me, whether it's someone I know well or not, I always first put the price for supplies right out at first--even if it means saying the fabric is $10 (or whatever you pay in UK)yard and the backing is $xx per yard, and the bat is $$ and then there's thread and needles, etc.
And be able to give an estimate of yardage needed. If that doesn't scare them off, then include your labor. If they still want the job done, get a deposit and put it in writing for both of you.