thanks for replies....
Update :- managed to get 4 x 135 AH acid batteries for 450 , they are italian make - got them from the sparky at the local Volvo
they fit OK and we are up and running
Ahh yes , not gel , AGM
, still have the disadvantage of not being able to see if they have a problem ???
first thing I dis with the new batteries is check the SG.
I think these will be cheaper option and less life than a better battery - but that suits us at present.
Kris - waiting for another BOAT moment ???