The Solartwin system I installed is now marketed under the name ThermaTwin by
DiscreteHeat. If you want to visit their site, it is here. It contains wide-ranging
information on their innovative system, presented in an extremely straightforward
and honest manner.
I purchased their DIY kit, which comes with very detailed and comprehensive
instructions, and the materials supplied are of high quality.
One point worth noting is that the pipes feeding the panel are far less visible, or
totally unseen, when the panel is fitted on a sloping roof - which is the usual place
for solar panels.
When sourcing some extra insulation - needed because my panel is not directly on
a roof - I mentioned the simplicity of the system, and was told by someone
'with 30 years experience in the plumbing trade'
that 'it would never work!'
Well, he was wrong! - It works a treat!
.