Re: Cold radiator.
I've had a surprise.
I was telling Tony about this thread and showed him all the replies. He decided without telling me, to have a go at it himself while I was out this afternoon.
I came back to a red hot radiator!!
I'm so pleased that he could fix it while suffering from Alzheimers. I never thought he would.
What he told me he did was drain the top ... When it didn't get hot he drained the bottom.
Hurrah - it worked.