Translucent Windows

After various suggestions on Model Rail Forum I have tried spraying some glazing to create frosted or translucent windows as required for example along the rear canopy wall for platforms 5 and 6.

Following some suggestions on ModelRailForum, I took a translucent document wallet cover (quite stiff plastic) you can see that untreated on the RHS, Then I gave it 4 coats of Vallejo matt varnish via an airbrush (2 each side) and also 3 coats of the frosted window spray that came in a can - this gave something much more like what I wanted - see the LHS.