Radiators hot upstairs and cold downstairs

[diselsamm]

I've a pressurised CH system with a combination vented cylinder.
I live in a two story house with 4 radiators upstairs and 4 downstairs. I recently had the CH pressurised and the cylinder also was replaced.
The problems is that the radiators upstairs are getting nice hot but the ones downstairs are not. The pump is working as I can hear it. I bled the radiators and left the lockshiled of the radiators upstairs a quarter closed and the TRVs are at 3. The lockshields for the radiators downstairs are fully open and the TRVs are at maximum. The boiler is Worcester 18ri and is downstairs.
Any advise on what I can try to troubleshoot the problem will be greatly appreciated.

 

[diselsamm]

I think it is from the gland/stem and tried to tighten it up, including all other nuts however it is still seeping... I think the whole valve will have to be replaced. Problem is I am having a difficulty finding a good heating engineer/plumber. Been a huge struggle.

 

[Ben-gee]

Whereabouts are you?
Nearest town/village?

 

[diselsamm]

Hi Ben-gee. East Devon. Thanks.