Since new I've noticed that there was a small amount of acid over flow from the battery cell breathers. A typical thing for dealers is to over fill the cells which results in acid bubbling out the breather on each cell as they bubble when charging.Anyway, I should have done something sooner as the acid has managed to bubble/ splash onto the rear underside painted section of the bonnet
.To neutralise the acid use Bicarbonate Soda mixed in warm water and enjoy the show
(lots of frothing as it does the work.)