Cucumber and courgette question

There's no problem with cross pollination for this year's crop. If you saved seeds to plant next year then you'd experience problems.

A little read HERE if you are interested in the subject (including how sweetcorn is an exception to the general rule.)

JayG - my system would not open your link but that is par for the course here. I was thinking of using some of last years left over packet sweetcorn as well as  my new stuff bought this year but they are different types -is this not a good idea?

Thanks JayG - you have answered my question. In the end I used a new packet of 35 sweetcorn seeds rather than two half packs of left overs, as I wanted a block of about 6 by 6. Last year the corn went down really well and I regretted not sowing more- I will try the link on my home machine which does not have all the restrictions that my work system has.