Originally Posted by
vicarious_MR'er
I know 3 or 4 hours is a short visit in the hotel, perhaps, but it's still probably worth it to me
Heathrow is a deceptively big place. As a UK passport holder, the last time I counted at T1 it still took me 45 mins from wheels down to getting into a car. T5 can be much better, but I'd say T3 is going to take as long as T1. Then you have to add in (I believe) non-UK/EU/EEA passport lines the weekend before Christmas just as all the flights are coming in from Asia.
You then have to get to the hotel. You'll get abuse and an oversized bill from a black cab who will be expecting a £100 fare to Central London. Take the Hoppa and it'll be an extra 30 mins by the time you wait, similar story for the service bus. Even if you arrange a car service, you have another 15mins to get to the car park, load kids etc....
Seriously, you're looking at not much over 2hrs in a hotel.
How about this - head to a hotel for breakfast, simply to kill some time? I believe that some, like the Premier Inn on the Bath Road, have kids play areas at the weekend and in school holidays. I'm sure others do this as well. Get there with a ride on a double decker bus for added novelty???