Finished just in time for Ethan's return from camp. I took off the old roller blind, re-used the block out fabric as lining for the new fabric (ebay find - from an interior designer with bolts of curtain fabric). Added rings, old venetian blind cords, stapled it to wood and screwed the wood piece onto the window frame. Took a while to rejig it to make it work and the rubbery block out fabric was a pain to sew with but overall I am pleased. All that's required now is acorns to tidy up the cords and another cleat. Apologies for the dark pics. I didn't finish til late in the afternoon and didn't take pics til after dark.