Just browsing around and came up with this. Certainly it is known how the left leans.
Of course it's not the kind of "evidence" you are seeking. Here's the link, hope it's ok to post it:
https://committees.parliament.uk/writtenevidence/68854/html/
Part 3: Left-Wing Antisemitism is not new
3.1 Antisemitic anti-Zionism is found most often on the far left of the political spectrum. There has always been a distinct tradition of left-wing antisemitism (see Steve Cohen 1984, Johnson 2015b).