I was working at Heathrow for a couple of days at the start of May and I went to a pub called "The White Horse". This pub is just beside the airport and if you are staying at any of the large hotels close by then ask at reception and they will send a car to pick you up. Then, at the end of the night, they will take you back to your hotel. This is free if you are having a meal there, or there are a few of you. I liked this pub as the food was good and the selection of beers were ok, but most of all it is a real pub, not a rubbish, expensive hotel bar.
This is a beautiful place and if you can I urge you to visit. The job also involved putting a PA into "The Boathouse", this is a great restaurant and bar right on the shores of Loch Lomond. Check out the photos below, the first one was the view from my room and the last one was taken at the barbecue at the boathouse.