Washable heavy curtains (Gerrards Cross SL9)

I am hoping to give a new home to some curtains. They must be machine washable, and I prefer a heavy fabric. The ideal would be three or four large full length curtains, as I can then cut them down to fit our windows. I can collect at a mutually convenient time from Gerrards Cross, Amersham, Beaconsfield, Chesham and Chalfonts. Thanks for looking.