I think I know the answer, but before I make any changes I'd like to run
it past the learned body of this group.

On the wood burner I have a dump radiator on the hot water circuit. It
does not get hot. I suspect that I have got the plumbing for the
radiator in the wrong place!

The pipes for the hot water circuit come through the wall of the chimney
and go into a 28mm/28mm/15mm T fitting with the 28mm horizontal and
upwards (to the indirect cylinder) and the 15mm downwards (to the radiator).

I think that this is the problem. To improve the flow in the (dump)
radiator should I take take the feed and return above the pipes that
feed into the boiler, not below?

In other words should I replace the 28/28/15 Tee with a 28mm right angle
bend and put a 28/15/28 tee higher up the feed and return pipes?

Cheers

Peter