Flooded pot. The tree's roots had grown through and blocked the drainage holes. They also gone through the tarmac to the ground beneath, hence the stubbornness to move when I attempt to tip out some of the water. Was called away, and it was my older brother that eventually sorted it, and found those roots.

Drove* up to the folks for the first time in five years. Put some air in the car tyres first, thankfully. Only one was at the recommended pressure. Seemed to run better...

(* instead of lifts from siblings, motorbike, bicycle, and bus options)