Thanks for your reponse Mike and for the config line too, nice one !!
I suppose I could be accused of not reading the manual, I have but not as fully as I should have done on this topic, though it can be difficult to find references to items, you can sometimes find little snippets tucked away in spots you'd never expect to find them and of course they turn out to of the greatest importance when you do find them. I remember years ago, it was the first time I'd ever used interrupts and could I get them to work, I was trying everything, I was totally convinced I had all the right options set and in the end it turned out that I hadn't set the peie flag in the intcon reg, doing that fixed things, one I've always remembered since.
Thanks again
Keith <kayjayuk>