No worries I think I have a few ideas..
Thanks for all your help.
All this is part of the learnig curve at the moment very steep!
But I already Know 100% more about Mach and this forum and attachments than I did at the start of our discourse...
Of course this amounts to probably less than 1% of what I need to know but hey its's a start and I'm a fast learner.
Take it easy Jolyon