Could be part of the retro new build work.
It's quick and easy to deploy and will likely go live before the Fibre First work in Northampton.
My development was done under this work despite there being no FTTP rollout on my patch.
They have covered the vast majority of new builds around me now.
No surprise there's nothing on one.network as the ducts are new and should be clear, there shouldn't be any need for roadworks permits.
Mapgroup are 1 of the subcontractors OpenReach are using for the FTTP build so looks like it's coming to you.