Good morning Chiglet,
thanks for the information. I know the location of five Norcon Pillboxes between the Point of Ayr lighthouse and Presthaven sands but didn't know about the blockhouses.
The beach area close to the firing range that Danny was using in his SpitII is still littered with thousand and thousands of .303 and .30 spent projectiles. There is also some 50cal stuff, but far less 20mm. I had never thought about why there was such a ratio of 20mm and 50cal to the smaller stuff; until reading Danny's reply.
Interestingly, some .303 cartridges made in India in 1943 turned up in the area.