Is it correct saying that on the 1st August BTC was upgraded to segwit1x
and the split off chain known as Bitcoin cash was given a 2mb increase
to its block size (but didn't get the segwit1x upgrade)?
No, that is not correct.
Segwit (not segwit1x, whatever that means, nor segwit2x) activated on August 24th. Bitcoin Cash forked from Bitcoin on August 1st and increased its block size to 8 MB.
Also for the coming November fork is it correct that BTC which now has segwit1x
will not change and the split off coin B2x (or whatever it will be called)
will be given the segwit2x upgrade? So B2x would now have the extra space
on the block given by segwit1x and also increase to a 2mb block size given
by segwit2x.
That is partially correct. B2X, is activating the Segwit2x idea which doubles the block size. The maximum block size for segwit2x is actually 8 MB as Segwit already increased the maximum block size to 4 MB.