I tested with City, an almost all british team after 5 years managing it ( the goal it is to make it 100% all british, although many players are **** ) and Hull. Both saves it is doing great.
One thing that has to be changed. You should check the Mr. L table for a tactic with a lot of goals scored from corners, and change your attacking corners set up, since they are terrible. Most probably the tactic will get even better, if that is possible, if you change the attacking corners setup.
I had 1 loss in 40 games with MC ( 39 wins, about 5,6 games where I conceded ), with british good players, but not Messis or Neymars, and that loss was a hard punishment. The opponents had 4 shots at goal, 2 on goal, 1 CC which was a penalty, I had a red card, and lost 2 1 after having around 20 shots and 3 CCs.
Hull went up from mid table to 2nd place in 15 games in the second part of the season with an average team with absolutely no star, not even on loan.