Thanks Eileen. I wonder why that site didn't come up when I googled - perhaps I was impatient and only looked at the first google page
. So it is available but a bit on the pricier side.
Nanna and Lindadragonfly - thanks for letting me know you've used ordinary card successfully. I attempted to yesterday and I think I must have had my brush too wet. I have one of those water brushes with the reservoir but I think it must have been a cheapy one rather than the Aquabrush (is that the better brand???). Mine just seemed to get too wet. I have a couple of ordinary brushes but they are the very small sizes, I think I will get a bigger one and try again.
Thanks again. I'm full of questions lately