"Is it split or is it two separate parties? "
There have been divisions between the warring groups, true, but to a degree, Brexit gave them a reason to bury them
Amnesty has reportedly denied that they reported that the knee-on--neck technique - that was a branch of Amnesty, they have not denied that Israel has trained American police forces - how could they - that has been a fact since at least 2013 when Amnesty first raised it   
This denial appeared in 'The Spectator', owned by the same press magnate who owns The Daily Telegraph
When Boris Johnson was editor he was accused of publishing a racist article aimed at Nigerians - a journal to be trusted on matters such as rcism

It is unclear exactly what Maxine Peake said about her statement, as far as I can find it has not been quoted in full - just the one line
That is beside the point - there is no question thet Israel has been training American police forces, just as there is no question that the technique that killed Floyd is used by Israel against the Palestinians
These are proven facts, whatever way you car to try to sidestep them

As far as political Parties being able to work with each other - following Brexit, political parties ban no longer get a consensus of their own elected members and are at odds with the rank and file membership
Starmer stands to become part of this ivory tower group who have been totally ignoring the wishes of those who elected them
That is the circus that Parliamentary Democracy has now openly become
Go ask the old-school Tories who were kicked out of office en-mass for not dancing to the music from the top
We have a hand-picked Cabinet dictatorship in Britain, as things stand at present
Jim