Stuart Horine

Thanks so much for the replies and help, however, It seems it was all a red herring... I had tried to re-write things, for example, by saving the state to disc at a certain point and reloading and ...

Hi Jaromił, Thanks very much for the tips. No joy. I have got further, however, and I am now stuck at a different place. It is now producing a solution, however, when I try to extract the value of ...

You hero! Thanks very much.