I've been very happy with the glass window I bought from MGF Mania. The material was a perfect match for my Mk2 hood. Peter does complete hood replacements including the Mk1 - while I don't own one of these, you may want to take a look. He was very helpful about shipping to the Highlands of Scotland which is apparently as far from parts of Englandshire as Australia.
http://mgfmania.com/shop/catalog/browse?sessid=HAwtJsMUahTfTkBWSUShygpo8HhpPy67mdkYyhmg0naVrms5R9qfBSvXM7WyBSsx&shop_param=
Richard
1.8i Mk2 Solar Red, 16 inch square spoke wheels, MGFMania hood with zip-in glass rear window, DRLs, Kmaps ECU, Pipercross panel air filter, MGOC Supersports back box & some cockpit bling