OK, thanks for that Adrian - I also found an adaptor
http://uk.farnell.com/jsp/search/productdetail.jsp?sku=1426185
so I can connect it to my stripoard (yes, stripboard smile )

Didn't realise about the isolators - the external psu is a 12v one and the internal board looks like it's purely going to run from the RasPi 5V so I thought they were needed.
_________________________
LittleBlueThing Running twin 30's