Gentlemen, the OP has commented that he got full heat from the downstairs rads when he closed off the upstairs ones, so given the correct amount of pumping pressure all rads should be made to work properly.
OP. I suggest there are some things you can do to alleviate the problems yourself.
1. Start with all upstairs rads turned off at their TRV.
2. Confirm that, as before, all downstairs rads work properly.
3. Start by turning on one upstairs rad and monitoring its inlet and exit temperatures - you may be able to gauge this by feel. Adjust by closing this rad's lockshield valve by 1/4 turn at a time until you get a noticeable temperature difference between inlet and exit, nominally 15C. You will need to wait at least 15 minutes between each adjustment, so this exercise should be done over several evenings.
4. Repeat for subsequent rads, finally checking that each rad has a similar temperature difference.
The main cause of poor balance in a heating system, in my opinion, are towel rads which often don't have lockshield valves that can be locked.
OP. I suggest there are some things you can do to alleviate the problems yourself.
1. Start with all upstairs rads turned off at their TRV.
2. Confirm that, as before, all downstairs rads work properly.
3. Start by turning on one upstairs rad and monitoring its inlet and exit temperatures - you may be able to gauge this by feel. Adjust by closing this rad's lockshield valve by 1/4 turn at a time until you get a noticeable temperature difference between inlet and exit, nominally 15C. You will need to wait at least 15 minutes between each adjustment, so this exercise should be done over several evenings.
4. Repeat for subsequent rads, finally checking that each rad has a similar temperature difference.
The main cause of poor balance in a heating system, in my opinion, are towel rads which often don't have lockshield valves that can be locked.