Web pages not loading correctly on Vigor 2862 Ln LTE when using ADSL (ping spikes too!)

It's been a strange week; we've had 2 broadband migrations with problems. The first was a circuit moving from a VDSL to VDSL; for whatever reason it got regraded to ADSL. When migration was complete a new 2862 Ln was installed and from there the trouble began.

The second was ADSL to ADSL - when migration completed a new router was also installed, another 2862Ln for LTE backup

Web pages weren't loading properly, connections intermittent and strange ping spikes on the local network. 

It would apper that the 2862Ln routers come with ADSL settings set to PPPoE and an encapsulation type of LLC/SNAP unlike their 2862 counterparts which are PPPoA and VC-MUX

The fix, change them to the correct settings! It's very easy to miss though when you're so used to the normal kit being right :(