It's not April fools. So it must be real! (
)
In all honesty, very interested.
I'm thinking it's a system in some ways similar to DI, with a special type of embedded filter media that can be recharged by flushing it with special chemicals. The flushing substance is the £2 to £4 a week.
Since it fills from tap pressure it's quick, because all contaminants are retained in the filter media there is no need to simultaneously have water go down a drain to remove solids from the membrane surface. Simplicity comes from water in water out. Just a few connections necessary.
I would expect DIY installations almost immediately, as soon as the technical details are known.