Okay people, so, to whom it may concern:
NATS told me that they are not in a position to be able to tell me if the tests on Tuesday (in Whiteley) will be cancelled. They also said the weather forecast looks positive with no more snow predicted, so it should be fine. However, they cannot guarantee it (obviously) because the weather could change at any point.
They also said that if I am worried in any way, I should cancel my selection date and wait for the dates from April 2011. Finally they said that if I want to take the risk that is fine, but it is unlikely they would be able to let me know an
answer until Monday (the day before).
So here you go, for all those who may be in this situation. In case they cancel the tests, we will surely have to wait until April 2011!