I used a minimum/ maximum thermometer in the poly tunnel to check on the temperatures and it did drop to zero inside. Luckily, no frost damage occurred, but just as well I took the precaution.
There is a big difference in the tomato plants in just over a week from when I purchased them. They were starting to get 'leggy' so spacing them out helped a lot and I planted them in the raised beds today.
Last week This week