problem after rads off

Hi,
i recently took off 2 rads in the same downsatairs room to respray. I have put them back on and now have no heat downstairs.
upsatairs is luke warm as is the hot water.
The boiler is on for a minute or two and then of for a couple then back on.
Not sure what system details will help you give me some suggestions but we have an oil fire boiler, a hot water cylinder in an upstairs airing cupboard and a header tank in the loft.
All the rads have been bled. The pump was replaced last year.
Any help or suggestion appreciated

try bleeding the pump

tried that - bit of air came out. Still not right though. Those rads that get hot are now getting fully to temp and the water temp is good to. I think I need to work out the order that the rads run so I can work out which specific on is causing the problem

Run the heating, turn all other rads off apart from the problems ones, wait until they get hot and then turn the others back on until the heat feels even around the house.