I freeze a lot of allotment veg, always blanch it for one minute after the water has come back to the boil. I no longer plunge the veg in cold water. Instead, I strain the water away (into another saucepan to blanch another batch, no need to use fresh water for each batch) and then spread the veg onto dry tea towels. The residual water dries quickly so the veg is much drier when it is bagged up. The veg cools down quite quickly too.
Our veg has never turned black, no ideas on that, sorry.
Frank Field, Labour Peer has died, aged 81y.
To think that London, or anywhere else for that matter, does not belong to any one demographic