I've been reliably informed by a brewer at Adnams that this piece of kit is a Pre Run Tank or Underback. It is used to collect the wort that comes off the Lautertun. I took the shot on my recent tour of the brewery. The tour is very informative, you get to taste lots of lovely Adnams and you get a free bottle of beer.
I met a guy who was on the installation of this plant when they came to do some remedial work on our Huppmann plant. Nice fella, likes his beer, and the ladies, and has no reagard wahtsoever for UK health and safety rules…