anglo irish treaty
artillery defences
battery
boat
breech loading
british army
british fortified site
coast artillery
coastal
concrete caponiers
county donegal
defences of lough swilly
disarmed
extensive ditch system
fanad
first world war
guns scrapped
headland
inishowen
ireland
irish army
irish coast artillery
irish free state
lenan fort
lenan head fort
lough swilly
operational
royal artillery
royal artillery institution
second world war
ship
sovereignty
treaty ports
ww1
ww2