Is there anything left at which the UK or England is world-class?

I don't mean being great at being a once-great power. 

The wine suggestion is maybe a bit premature. Every vineyard tour I've done in England, the host says "what kind of fruit notes are you getting ? " and I'm thinking "maybe under ripe apple, but beyond that I'm struggling"

We are actually really good at engineering. I've worked on projects that were the first of their kind

Computer games is another good one. Rockstar games that made the highest grossing entertainment product ever - grand theft auto 5 - is a British company

We're also pretty good at AI. Largest technology acquisition ever I think is still Google taking DeepMind

Motor racing - every decent F1 team bar Ferrari is British (although some race under sponsorship flags of convenience).

Actually sport in general.  The four great individual sporting achievements are Wimbledon, Tour de France, world heavyweight boxing champion, and F1 world champion.  Britain is one of only three (I think) nations to have had winners in all four; the only one to have had more than one in each category; and not so long ago had all four at the same time.

On top of which England/GB has won world titles at all three main football codes, plus the cricket at two.  

We've even got a winner in skiiing now.

Universities

Pubs

Theatres

Film and TV making

Sport

Libraries

Road Safety

Music

Festivals

Preservation of historic buildings - in particular the NT

Public gardens