This is the main UK society for people interested in photography and it has various interest groups including the 'Nature' one, whose members are particularly interested in wildlife photography
This is a friendly local group whose members are people living in London who are interested in birds and nature in general. Organises monthly coach trips to birding sites, and a programme of indoor meetings
This YouTube channel has a steadily growing number of videos on birds and wildlife in general. They include 2 presentations that I have given to the group - on wildlife of the Masai Mara, Kenya, and on Sri Lanka's wildlife.