thanks all for your replies just a bit of fun to keep the old brain box working and so AndyRVTR was spot on together with the plan of the potato clamp and your correct Yorkie I did know the answer,
my late father-in-law used to clamp his potato crops every year and he grew his own straw on the allotments to that's a bit too much hard work for me I'm afraid, but his clamp kept the potatoes frost free and they lasted well into the spring
thanks, all RW