That is a Iron caisonne so not Mulberry. There are loads of these things aroung the coast especially in areas like Felixstowe and other old large ports.
Definitely caisson number 449 which is concrete and part of the Mulberry at Arromanches.
Arromanche and the Pegasus bridge are the only WW2 sites I've visited on that bit of coast. I'd like to do more but the wife keeps dragging me further south for the weather.
Thanks for the Hobnob, although I have to dunk them these days.
edit: If anyone has even the slightest interest in WW2 you should visit the V2 bunkers at Eperleques just south of Calais.
V2ROCKET.COM Watten Bunker / Eperlecques Blockhaus
If you're heading down South, Oradour - sur -Glane is worth a look Oradour-sur-Glane 10 June 1944, and the submarine pens at St Nazaire.
Yes, went to Oradour in August this year. Been trying to get there for nigh on twenty years but was never really close enough. You don't realise how big the village is until you walk around it.
St Nazaire is on my to-do list.
I've got no idea what Mastodon has found this time :-(