For those who, like me, have been struggling with this new website I have discovered that it doesn't like places like EGTU. If you enter this as your destination it just sulks without telling you why.
Entered EGTE instead and it worked. I had previously spoken with a very nice man at NATS and he couldn't tell me why it wouldn't work. I explained exactly what I was doing and he couldn't get it to work either. I am waiting for him to fax me with the answer.
He did agree that this was not the best bit of software ever written. Hopefully they will sort it out quickly.