My husband, in-laws, our 1-year old and I are supposed to arrive in London heathrow at 11pm. We wanna take the heathrow express to Paddington, then maybe the tube to waterloo station (we're staying at the County Hall Premier Inn). Just wondering if we'll be too late to catch the HEX after going through customs, grabbing checked baggage, etc... If I'm not too late, is it better to buy the ticket now, or what til I'm at the airport. If we are too late for the HEX, then what's the next best thing to get to our hotel? Also, how late does the tube run?