Radiator Problems

I moved into my house a year ago. The boiler was replaced with a combi boiler which works fine (about 2bar pressure if you needed to know). I have 5 radiators (all existing). 4 working fine, 1 in dining room was disconnected. I recently got around to reconnecting that radiator. It is now working fine, in fact it is the hottest of the lot.
However, since putting it back onto the system, 2 other radiators are a lot cooler, one in fact may as well be turned off as the heat it gives out it pathetic.
All the radiators have adjustable thermostats on them, and at the other ends, they have the white valves (sorry don't know the correct term).
Have bled all radiators until nothing but water sprays all over my walls.
Any advice?

balance the system

look in reference

hi the radiator that you took off /the white valve close it fully then give it half a turn open for this exersice open the thermostatic valve fully leave the radiator to warm up what you are looking for is that the top of the radiator is hotter than the bottom this is called balancing the system you should carry this out on all your radiators do it over a period of time by the way once each radiator is hot put the thermostatic valve back to a lower setting