Some years ago I bought some 2mm thick "Glodex" (styrene - I think) sheet from a local plastics supplier who no longer stock it. The stuff I bought had a sort of "rivulets of water" effect on it, making one side totally smooth but the effected side somewhat bumpy.
I used this stuff as a secondary-glazing on windows which I wanted to make seem as if they'd been glazed with an obscured glass.
I think I remember seeing the same stuff in B&Q, but visits to my local B&Q now only show 2mm- and 4mm-thick sheets which are completely transparent - ie nothing with any form of obscuring on it. I notice also that the sheets available no longer say Glodex on them, which makes me wonder if B&Q's supplier has changed.
Googling for "Glodex" showed nothing. Does anyone know if the stuff is still available, or if any other manufacturer makes the equivalent stuff?