Dave Liquorice wrote:

I've had a quick look and
it seems that the external box is probably a coax to fibre converter,
as this service is delivered over the existing coax network not FTTP.

sounds unlikely.

Is the O/P in an openreach location, or a cityfibre location?

https://kenstechtips.com/index.php/vodafone-gigafast-broadband-review#Gigafast_Towns_and_Cities