They aren't, its still down to fund managers to decide what to invest in, Pension funds carry risk, they can go up or down eg Truss's time in office saw DC schemes lose a great deal of money as gilts lost value.
As far as i can see, the Govt is allowing the conditions for managers to invest in, not ordering them to invest in x or y.
It also seems to only be applicable to the 86 council run schemes, currently run by council officials.
On foreign ownership, thats happened under the old regimes/policies, selling everything off to the highest bidder, these assets are then sold again again.... if a UK airport is good enough for a foreign pension fund to invest in, why not a UK one?
We seem to be heading for more nuclear and more on shore renewables, why not have these backed by UK funds and not Australian ones?