Full marks to Sacha and others who picked magnolia stellata!
The previous owner has finally forwarded me some details of some of the plants -
amongst others, these were named and you were absolutely right.

She suggests pruning for shape (I don't know how old these are but they've been
kept quite small for a plant that seemingly can grow to10 feet). Does this
require cutting back older growth to encourage new or can it just be approached
as a short back and sides?