Finally managed to complete the survey of the new M1 J8 (Hemel Hempstead). Also discovered that the A414 is being extended from Hemel towards St. Albans, and as a result the M10 is being downgraded to a trunk route (as it's now possible to drive this route without joining the motorway). I have only removed references to the M10 around the M1 junction as I did not travel to the far end of the M10 to confirm the road signs at that end have been changed to reflect the new road status.

I've removed all construction tags from this junction; although the roadworks continue, the overall road layouts now seem fixed.