I spent about 3 weeks in the UK in the summer, including Northern Ireland, Wales and one final night at a hotel at Heathrow.
Using 2 different credit union credit cards, I literally "tapped" almost 100% of the time. I never needed to sign for any CC charge. That included in small and large restaurants, at shops and grocery stores, at tourist sites, for train tickets, in taxis and even on local buses in Wales that only took credit cards, much to the surprise of my B&B host in Llandudno who thought I'd need cash.
This was my first European trip since 2019. I found tapping very easy and convenient. Some might say it's too easy and convenient, but I like it both at home and abroad.
I did get a total of £100 in 2 separate withdrawals. I used that cash primarily for laundromats, round up tips and tips for housekeeping staff. I brought home £40.
Although I wasn't really in London this trip, I'd assume your experience would be similar.