The sheep you most often see dotting the countryside around London seem to be Dorset. Prolific reproducers, they almost always have twins, and this time of year the fields are full of two bag-of-bones little lambs shadowing their mothers.
Farming and agriculture is a big business here. Being a fairly small island, there is a big point of pride that goes with raising almost all of their own meat- even most supermarket chains will advertise that they sell only British products in their meat department. As soon as you leave the city of London, you will find farms everywhere, punctuated by tiny ancient villages and copses of tall trees. It's really quite scenic- I get how in love people are with the rolling hills and fragrant green countryside in England.
Here are some Dorsets I encountered one day on a walk: