Cotswold from London

If you are staying close to Paddington, consider doing it yourself. You won't see Stratford and several villages, as some of the tours somehow offer, but it's easy enough.

Train to Moreton-in-Marsh, which is worth a wander around. Bus to Bourton-on the-Water; get off on the first stop in Bourton (ask driver) and walk to Lower Slaughter (signposted). Walk on to Upper Slaughter. Back to Lower Slaughter and lunch at the Country Inn. Photo opportunities.

Walk to Bourton and walk around. More photo opportunities.

If still early, visit Stowe (on the same bus line) on the way back to Moreton.

Also give some thought to using this service from Moreton.
https://www.gloucestershire.gov.uk/transport/the-robin/where-can-i-travel/cotswolds-north/

Whoa! Thanks for the information. This was an option I did not know was possible or adviseable.

I agree this is the best way to see the Cotswolds from London without a car. I also suggest walking all the way from Bourton-on-the-Water, via the Slaughters, to Stowe-on-the-Wold. It's not very far. Stowe-on-the-Wold has some great places for photography including the famous door to St Edward's Church, which you can see here: https://www.cotswoldsconcierge.co.uk/the-doors-of-durin-st-edwards-church-in-stow-on-the-wold/

Then it's easy to get a bus back to Moreton-in-Marsh for the train home.

How many miles is the walk from Bourton to Upper Slaughter? Thanks

I'm guessing no more than 3 miles? No steep inclines.

Once you're out of Bourton, a footpath off the main road leads to Lower Slaughter. Some really pretty cottages here. Walk through Lower Slaughter and past the mill, where a second field path takes you to Upper Slaughter. There's a church up there and another hotel/restaurant.

Being an active 70 year old and traveling solo......I am still really liking this option.

Thanks Gunderson.

Robin service and bus route 801 info:

https://www.pulhams.co.uk/busservices/timetables/

If you take an organised tour, there's always a danger of sitting next to a Jackson Lamb type of character.

WARNING, VERY STRONG LANGUAGE; DO NOT WATCH IF YOU ARE EASILY OFFENDED

https://www.youtube.com/watch?v=5JMJhwpN2qY

Train to Moreton-in-Marsh, then one of these tours;
https://www.gocotswolds.co.uk/

London Walks has a daylong tour about twice a month. Looks like it could be good. https://www.walks.com/our-walks/the-cotswolds-excursion/ The problem would be you'd have to move with the group and not linger in one place that might really grab your attention.