Long Layover in London-best area to stay from LHR

Consider Windsor rather than London. It is very close and has lots to see. Just walking along the Thames is a wonderfully relaxing experience. Last time I did this my B & B arranged a private car to pick me up

Or take the Heathrow Express 15-20 minutes to Paddington Station, stay in a hotel nearby, and enjoy your evening and morning in London. The Paddington neighborhood has lots of hotels, none of them outstanding but you're just looking for a place to sleep. There's a Hilton right at the station, most convenient if it's in your budget. I stayed several nights at the Delmere Hotel, a Best Western property a couple of blocks from the station, clean and comfortable enough for one night. It's on a block full of hotels, and the RS guidebook recommends others nearby.

You'll probably be too tired to do much that evening, just have a nice dinner and go to bed. Get up as early as you can to see what you can in the few hours you'll have the next morning. Three tube lines stop at Paddington so you'll have lots of options. My suggestion would be to take the Circle Line to Westminster, look at the Abbey and Houses of Parliament and the river, walk up Whitehall to Trafalgar Square, head up to Piccadilly Circus and Oxford Circus, and take the Bakerloo Line back to Paddington. You could vary this walk in many ways depending on weather, how well you walk, and interests. Or maybe there's one special place you want to visit -- church, museum, palace, or whatever. But you should be back at Heathrow by 12:45 if you're flying out of Europe, 1:45 if flying within Europe.

The Heathrow Express is the fastest and most expensive way to get between LHR and the city, but tickets bought online well ahead of time can be very cheap. They don't commit you to a specific train time, only to a specific day, so you don't have to worry if your flight is late or you have immigration delays.

This is great and along the lines of what I was thinking might work, i.e. taking the express to Paddington. We are flying to Rome, do you think 1:45 is good?