"There is no extreme left wing on here."
Of course there isn't, there never has been
Easily proved by asking those who believe there is to produce examples, but we know from past experience that would be a waste of time.
There is not really an 'extreme left wing' in Britain - the UK has never really produced one.
The left Parties, many now moribund, have mainly opted for theory rather than action and, as far as I know, have never advocated violence as a policy - cold be wrong, of course, but again, a waste of time asking for examples
Anybody can fling about names - bit more difficult to substantiate the labels they choose to use.

When it comes to right extremism - take your pick
Racism is the jewel in that particular crown
Brexit motivation, Islamophobia, antisemitism-proper (the hatred of Jews), religious and cultural sectarianism.... all advocated, financed and carried out by the right
There extreme poverty rising from the inequality of our society, the debasing of the British people by associating with despots and selling them arms to oppress their subjects, the refusal to provide sanctuary to their victims - that makes British right wing extremism International

There Stan - I've shown you mine, now let's see yours.
Jim Carroll