already been there, if you read through about 3/4 way down the page there are a couple of constraints, the one that concerns me i've copied below

"The second shortcoming is that this technique at present does not cater for cells that are coloured due to conditional formatting"

the result being that this will do what i already have in use but not what i'm trying to achieve.

thanks for the link anyway, couple of things in there that may be useful in the future