I removed the torx bolts and replaced with something much better. Also took fin_676 advice on the impact driver, worked like a charm. My 'problem' is solved.
Thanks to all the posters on here. I only wish I knew more about motorcycles so I could actually help on this forum the way I have been helped.
If you stay with the forum long enough and pick up your tools often enough by asking questions and a wee bit of trial and error you may well at some time be in a position to offer advice and it always a good feeling to be thanked for advice given so thank you for your reply
just one other wee bit of advise because you experienced a common problem i always put a wee bit of copper grease on the threads of the bolts holding on the derby cover and that helps with removal
Brian