Frost and Raised Beds

We have a threat of frost here in East Anglia tonight, down to 2deg C. We are not in a frost pocket.
I have potatoes, sweet corn and dwarf beans in raised beds made of scaffold boards, so about 9 inches above ground level.
Am I right in thinking that they will not be affected by a ground frost?

I agree they will need covering with fleece or cloches  Even newspapers will work as a last resort - if nothing else is available!