The church of Colleville sur Mer in 2010, for comparition. The small green sign at the entrance of the Cemetery indicated that soldiers of the Commonwealth are buried there.

Church of Colleville sur Mer, then and now

The web got me to info on the Bulgarian helmets fast.  The model is M36.  Types are A, rolled rim, B&C, unrolled rims, different liner details.  This image shows a type A.  In the mid 1990s I found one of these at the Athens flea market.  I didn't know what it was but bought it.  It had a great, clearly old, large, handpainted red star, edged in white, on the front.  Wish I'd kept it.  It was probably from the Greek Civil War following WW2.  I had a very difficult time finding identification then.  Took about 20 minutes last night.

Bulgarian M36A helmet

The gun is now facing West, originaly it covered the beach to the East. A plaque on the spot reads the following: "It's crucial positioning protected the gun of any direct fire from the sea, and it could cope with collateral attacks from the beach, the boardwalk and adjacent streets. After having put out of combat the first allied tanks in the morning of June 6th 1944, it was reduced to silence following a heavily armed attack by 3 other tanks". I chose this photo because one can see part of the damage to the bunker, the barrel of the gun was also damaged but can not be seen from this angle.