Solar installer for heat dump installation

We have a solar tube system that is working very effectively. It was installed less than a year ago.

We would like to get a heat dump installed by a reputable solar system fitter.

We had a fitter out from a reputable firm about a month ago but he hasn't provided a quote.

Any recommendations?

What area are you in? I will hopefully know somebody in your area.

It will also be better to use your heating system as the heat dump rather than the solar circuit. This can be done using a circulating pump using the heating circuit coil to dump heat out of the cylinder and into the radiators, thus lowering the hw cylinder temperature so it can take more heat from the solar circuit.
The pump should be wired through your spare relay in the solar controller. The controller is then set up to switch on the pump when the water temperature hits 75C and switches off when it reaches 65C.