Could someone help me please with lenght of personal statement? I can't fine any precise instrucitons. Is there some advised number of caracters? I wrote 2 pages, is that too long/too short? I'm applying to KCL, QMUL, Edinburgh, Nottingham...

It depends on the uni. I have applied for QMUL and KCL. QM requires to keep it brief (one sheet max). KCL recommends around 4000 characters but you can upload a longer one, I did it and got an offer.
Good luck.