Thanks all so far. Your right extopia, I'm looking for a concrete barge/strip on the gable ends.
Ted i think the typical barge details for slea head area, would be a typical coastal area detail - i.e a varly high barge, probably in the region of a full block height above ridge level. would I be right??
The detail I'm looking for, would be for a more subtle plinth - probably 75mm to 100mm above the ridge level. This will make the barge more difficult to seal from water, as I'd imagine lapping the lead over will be tricky.