tigg Thank you. I have had another "play" this afternoon - I really would like to be able to do this in camera. Thanks for your helpful words.
vera I think that your first photo with the church should be more overexposed with a white sky, it would be better. Than on your camera Oly, you can adjust the brighness of each photo.
agnieszka bladzik i think many good double ex that you can find in the net is made in photoshop by marging two photos, I see you are trying with oly inbuilt function - i aslo never managed to take good double ex with it, but maybe i will try now :D