News wrote:

The local DSLAM cabinet

MSAN they call it for VDSL/FTTC, DSLAM implies ADSL.

was installed outside our house
a year ago, and since then, there is often an Openreach van there, with
a little man doing things in the cabinet. Daft question perhaps, but
presumably an engineer is not required to make a connection within the
cabinet every time someone switches to FTTC broadband?

They shouldn't need to visit the new cabinet for each FTTC migration,
because they install a multi-pair "tie" cable between the old and new
cabinets, but they do need to visit the old cabinet to divert each line
to the new cabinet, and the voice part back from the new cabinet to the
exchange.