Thanks for the replies, i've done a quick google search and it appears the functionality of the fog light isn't checked, it's the sharp glass which might be an issue.
Think i might call the test centre in the morning and ask.
Rear for lamps are tested. If it is not showing any white light when lit it sould be okay. If it is showing white light should fail. You can get lens tape if you want to go down this route. Halfrauds sell it.
As stated above the front fogs are not part of the test but if the lens is sharp and could cause damage to a pedestrian it can fail for sharp edges, if you are unsure on it just cover the broken light with some gaffer tape, I test cars and have never failed one yet like this.