I need some opinions from my UK based FT friends...

I'm going to be in London for a few days and was thinking about taking a day flight up to Newcastle and back. I found a reasonable fare from LHR on BA. The flight would depart LHR at 0845 (IIRC) and get back in at 1900.

1. For a domestic flight, how early to get to T5 (no luggage planned)? I would be staying at T4 the night prior.

2. I did look at the National Rail, and it is slightly cheaper, but the train tride is almost 4 hours each way. However, if I have to be at the airport 2 hrs prior for both flights, I'm not really saving much in the way of time.

3. I've never flown domestic in the UK before, so are the queues as bad for those flights as they are for international flights (my point of reference here is BA T4 departures to the states)?

4. Luggage storage in T5?

Any input is appreciated. In NCL I would be using public transportation to get around.