Central Heating Radiator not working? Is it air, sludge or need balancing

Подробнее о видео

Some simple checks and fixes any one can do if you are having problems with a radiator.
If you need any plumbing parts here is my Amazon shop link.
Saved money on plumbers coming out? Want to donate a £1.00 and keep our spirits up? Here is the link.
Many thanks Al and Jan.