Hmm, it's not been my experience that there's no tipping in England. I can't speak for the rest of the Uk, as I've never visited.
I've not been anywhere outside of london, but I do recall there being times where I did tip and did have conversations with servers about tipping. I try to ask what social expectations are when I travel. I've not had people refuse extra tip on top of service charge, and I've done that in places where the hospitality was something I found exceptionally good.
You also get instances where a mandatory service charge is already added. Whether you consider that tip or not is up to you. I think it counts as tip.
https://www.tripadvisor.com/Travel-g...Etiquette.html