NowTV (Sky) VDSL Strange 5mb connection issues with Opnsense

[windswept321]

I have a thin client running Opnsense with 1 gigabit PCI card and a built-in gigabit adapter (AMD G-T44R Processor, 4gb ram).

Testing with an ECI openreach modem, I get an initial connection of 5mb, which drops to 4mb when reconnected, then dies after. No reconnection will occur at this point. I then need to switch to the NowTV box to get a working connection again to try again or to have reasonable speed.
I'm wondering if something is wrong with my connection settings as the guide I followed mentioned a setting which seems to now be missing from Opnsense -  Directly send SOLICIT.
Here are screenshots of my interface settings.

Does anything seem incorrect or is there likely to be some other issue I'm not understanding here?