@shane.uk
It's very polite to introduce yourself and get known to the community. Besides, next time please consider opening a new topic instead of writing on any that's not related, and not hijack another one's post. You can give a look to the green sticky posts at the forums main page.
And about what you asked, Conditional Format, New Rule, Formula, =OR(YEAR(TODAY()-A1)>0,MONTH(TODAY()-A1)>6), set format to background red, apply to A1:Xn, where X is the last column in the range and n its last row.
Regards!