Dunk
Established
Hi Dunk,
As I believe you are in the U.K. Maplin stock an ultra violet curing optical cement that would solve your problem. It is called Bondloc, I have used it several times with success. I also have some Canada Balsam which you are welcome to try, that is if you can go through the hassle of heating the elements to cure it properly.
Keep up the good work,
normclarke.
Thanks Norm ... will bear in mind when the lenses are separated. And if this project is successful the 35mm lens will need similar treatment.
Cheers
dunk