Like I mentioned in the original post, according to Whites it's safe to go up to 18V. That was one question of the other forums where that question was answered by Reg after he conferred with Whites engineering.
Ooops ! I thought that voltage number was for the other two machines and not the sl Chris . I'll have to reread that post again .
"Honesty is an expensive gift ,
so don't expect it from cheap people"