I wondered why the "Z" designation and did a search but couldn't find anything.
"A Z Battery was a short range anti-aircraft weapon system, launching 3 in (76 mm) diameter rockets from ground-based single and multiple launchers, for the air defense of Great Britain in the Second World War. The rocket motors were later adapted with a new warhead for air-to-ground use as the RP-3."
- Wikipedia
Found more pics though.
This is photograph H 21141 from the collections of the Imperial War Museums.
War Office official photographer, Taylor (Lt)
"HMS Ashanti was a Tribal-class destroyer of the Royal Navy. Following the style of her sister ships she was named for an ethnic group, in this case the Ashanti people of the Gold Coast in West Africa. She served in the Second World War and was broken up in 1949. She was the first of two Royal Navy ships to bear the name Ashanti."
Effects left by a 22,000 pound 'Grand Slam' bomb dropped from an Avro Lancaster, which pierced the reinforced concrete roof of the German submarine pens at Farge, north of Bremen, Germany.