I live in Arizona and fed ex said it would take about 4 weeks to get here but I got it 2 weeks earlier than planed so I would expect it to arrive earlier than what they say.
urm kinda.. mines out for delivery today im so excited i might just hug the delivery man lol "/ but yeah they are fairly accurate! may come a few day before "expected delivery date"
When I ordered mine in May I got it about 10 days earlier than first notified. Got my Apple case on time but my camera connector was tied up in Alaska for 4extra days and was 4days later. I have a second Zipad ordered and its due to be shipped Aug 23 and they say delivered Aug 26. That I DO NOT believe and expect to see the delivery date change. It was ordered Sat so that would be about 3 weeks.
I can't speak for the UK, but here in the US my iPad arrived on the day that Apple had originally said it was supposed to ship, 3 days prior to the original estimated delivery date.