You might be able to balance the rads to give more heat to the colder ones.
Even though a 5.0M head should be more than adequate for any CH system you could change the pump to speed3 which gives a 6.4M head, then adjust the ABV to say setting 0.55ish, if the system is noisy (or no improvement) then revert to speed2 and ABV to 0.45.
Even though a 5.0M head should be more than adequate for any CH system you could change the pump to speed3 which gives a 6.4M head, then adjust the ABV to say setting 0.55ish, if the system is noisy (or no improvement) then revert to speed2 and ABV to 0.45.