Penny has just dropped - do you recall the DIY trend -60/70s? for using sticky vinyl - all colours and "textures" (woodgrain, marble etc) that folks used to put on window-sills, larder cupboard shelves. You could get plain white - dirt cheap, and I saw some in a hardware store recently. Can't remember the trade name...recall it wasn't too good in high UV environment such we have in Oz outdoors, but I might give that a try as a cheapo alternative....