Radiator Bleed Valve

Albermarle

I'm not sure if I need to bleed the radiators. But, they do heat up quite slowly.

Have you tried opening up the lockshield valve more ? 

Rodders53

Sticky TRVs not opening properly and/or poorly balanced radiators will be a more usual reason for slow heating of some radiators compared to others in a system.
So unless they have a cold top and hot bottom air may not be the problem.

Very old radiator bleed valves may have an imperial size head so need a slightly smaller key to more modern ones (modern being now over 50 years, probably).
https://www.amazon.co.uk/dp/B0D9WHYT2K 

RHemmings

Thanks for the replies everyone. I'm not one of these vanishing OPs. But, I need to obtain the various bits of information that have been requested here. 

ThisIsWeird

At fourthousandfourhundredandsixtythree posts, I doubt anyone would consider you 'vanishing'

shiraz99

It looks like part of the valve has been sheared off. I had one on an old towel rail but it had a knurled wheel that you turned but it looks like that bit has broken off. You may need to use an adjustable spanner or pliers to turn it.