I was put in touch with Solartherm UK from our inverter manufacturers. The old equipment had popped its fuse, although we thought it was something more sinister. A quick test of the panels shows one was not even working. We had the original system by my planet, they have gone and we thought we were up the creek. Great service provided by some very responsive office girls, reasonable cost and we may have a nibble on some other gadgets at a later date.