It seems to have worked. Only the last frame was multi-exposed. The camera just kept winding on at the end of the film and never stopped, I hope I havent broken it.
The plastic insert is only placed in and is easy to remove. If I use the camera again I may try it with the insert removed. If its really a 25mm lens it will be my widest lens camera, I've wanted wider than 28mm for some of my project work.