The Adle systems I have seen all the radiators are connected in series.
Set the heating to high and run. Leave it for about a 10 min to warm up. Then check the radiators to see if they are hot from top to bottom. If some are still cool at the top , feel the out flow pipe of the radiator, if it's hot then its most likely air in the radiator, and it should be bled.
If outflow pipe is cool, then the pump speed may need to be increased to improve the circulation.
IF this doesn't resolve the issue it may need to be checked by an Alde approved engineer.