Do it!
I did methods and bio 3/4 in y11, and it is 100% worth it.
I didn’t do the 1/2 component for Bio, which did mean I had to do lots of work over the holidays to catch up - but I think I over compensated - and ended up with a head start on the content 😆
So yes, would recommend. Doing 4 subjects in y12 was a life saver.