Sorry for the late update. Had to wait for them to complete works today (was only able to complete works yesterday except for a small section closer to home as some office section closed at 3:30 or something)
So the OR engineer arrived and asked about details on what's been transpiring. Did line check and found the "same" High Resistance issues at the 30m (again) and around 400m mark (at the cabinet). And set off to see what could be done there.
Confirmed afterwards (after removing and replacing whole sections of the lines at those two locations), that there was "NO" Bridge Tap along the line (so that info on the Checker is totally a guess at best from info they get only and not an actual accurate detail). And nothing within the household which was acting as the Bridge Tap.
Not sure if a reset was issued, probably was as they were working, as when they came back, the line at calmed down to 6.0db downstream noise and getting 74mb rate, with speed tests showing 69-71 functional.
Glad I called in about querying that Bridge Tap and the slower than expected speeds.
Thanks all.
Got to go grab that modem/router MrSaffron suggested now.
J1NG