Dear NewDoverman and Alf,

I've been out of the office on-site for the last couple of days and have come back to find not a gentle nudge in the direction I should be taking my formula, some advice, or even an explanation of how to do what I was so desperately failing in, but a completely rewritten formula with everything working like a charm.

I sincerely appreciate all your help and I'm quite bowled over by it. I really didn't expect that. It's also quite educational for me as there are some functions in there I've never touched before, so it is interesting to see the mechanics of the formula and how these functions work.

You've made this girl very happy (as well as saved her remaining braincells)!

Thanks guys x