Speaking of the UK, they used a variety of materials and different types. They certainly used concrete, Im also fairly certain ive seem some made out of red brick. There was also some specialized types made in the southeast that were almost like a concrete garage, and could mount a 2 pdr, or possibly even a 6pdr antitank gun.
Ive not see pictures of Panther turrets emplaced outside Italy either. Did they use them on the Eastern Front? Strikes me as a waste of effort there.
A reasonable number of ex US 75mm were received some of which were pedestal mounted. It is not hard to believe that a number of these received some protection rather than being left out like the proverbial shag on a rock. They were considered to be 'coastal artillery equipment' but were really for beach defence.
About 8k from my home are some WW2 concrete emplacements for otherwise obsolete 18pdr guns that gunners arranged concrete mountings, overhead and other concrete cover. This was nominally to protect Port Botany from attack by Japanese torpedo boats... (yeah sure, 8000 kilometres from Nippon to Sydney). More likely to defend the nearby 9.2in battery from shore parties from Japanese submarines or cruisers.
The artillery personnel sent to this little battery were from an anti-tank unit to train local choco soldiers (chocolate - melt in the sun, nothing racial) in using emplaced 18pdrs against moving targets.
I am sure that the Brits / Cannucks / Kiwis had similar things happen.
The place was Henrys Head
A few years ago I was walking one of my annual pilgrimages to the site when I encountered two 'young' women
(well they were young to me) asking about the bushwalk to Henrys Head. They had taken a wrong turn and had walked onto a local unofficial nude beach, where the Henry's Head that they expected was not as expected....) I walked them to the proper place and gave them some history along the way.
Edited by DougRichards, 10 January 2020 - 2041 PM.