DIYrich, KnobCountry, Mikefitz thank you all for responding
Knew this was going to be quite a learning curve.
So the panels are actually rated a little lower! Vmmp of 41.3V, VOC 49.7V, lmpp 10.9A, V Temp coeff -0.29
The system was intended to be a 48V one.
So if panels in series is a hazard...