Follow up visit
We've cleaned out the dead hive and put the brood box on top of the surviving Langstroth. This will allow the bees to make use of the stores as well as cleaning the frames.
This hive still looks pretty weak. There's not much brood and by now the queen, who was new last year should be going strong.
The Warré still looks fine - the bees are happy! Must build myself another one.