Oh no, what about my tomato plants

I was not expecting a heavy frost last night. The tomato seedings have been out in the greenhouse for a week of so and are doing fine. I have been studying the weather forecast and was prepared to bring them back into the house if necessary.
This frost was probably forecasted but I missed it, rugby weekend, sausage rolls and beer etc. The Irish were very good again, a different class to all the other teams. 
The seedlings were OK this time. I must be more careful.