Thanks to all you Rootschatters for the help on lighthouses and lightships in Ireland. It turns out that the Commissioners of Irish Lights was the place to go afterall. I emailed them and within 24 hours they came back with the service record of both my Thomas Delaney relatives (father and son) nothing on the grandfather Richard as his records would be much earlier in 1840-50. However they don't have any family info on their lightshipmen e.g whether married, or what their addresses might have been, only County of origin. Still, I'm thrilled, Thanks heaps. Now it makes sense why all the men folk were not at home on Census night 1911.
Regards Canberragirl