After several problems with slate suppliers, the builder who is replacing the front roof was able to get nearly all the slates installed by yesterday and we then fitted the solar hot water panel frame and pipework onto the new roof. The panel came with flat fixing strip which we were told tends to break after a couple of years and the builder was able to source much stronger stainless steel brackets which fit around the roof battens and come out via a slot in the slates (covered with lead to seal after).
The 22mm pipes were run into the roof via holes in the slates and the lead flashing places were fitted, these still need to be made 100% weatherproof but this will be done before we add the tubes to the panel.
The water pipes have been connected internally to the rest of the system and was test filled last night and it has maintained the same pressure now for 24 hours so hopefully we have no leaks!
The brackets for the solar PV were fitted today and we are planning to install the PV panels over the weekend once the builder has finished all the weatherproofing on the rest of the roof.