The default is Alt Shift (on the left side only I think). You can choose other combinations.
Rolling these will toggle the KEYBs. BUT, I gather you've now removed one, so this will not work.
I much prefer the American layout, but load the UK version to be ready for when I need £s etc. (# normally)
#£#£# This can be changed by a menu that pops up from the EN on the task bar, but unfortunately, EN is used for both KEYBs so it doesn't work as an indicator for the key toggle method.
This keyboard issue. I carry one of a box of Logitech OEM keyboards I acquired to anywhere I'll be doing a lot of typing. Changing from one to another is a chore - especially on laptops where the changes can be bizarrely different. I use flat boards - how anyone can type on rows of boulders beats me. I can't imagine being able to go back to a typewriter.
We will now announce to the world I've added to the above with an edit. Pah!