Are all London properties at risk of subsidence?

Just got a survey back and there’s nothing too alarming.

One thing though, it mentioned that I’m in an area (London) built on potentially unstable ground. They specifically said this.

“The property is situated in an area that is at significant risk of Shrink-swell clay. Shrink–swell is the volume change that occurs as a result of changes in the moisture content of clay-rich soils.

Swelling pressures can cause heave, or lifting of structures, whilst shrinkage can cause settlement or subsidence, which may be differential. You should make sure that all drainage is kept well maintained and ensure that trees/bushes do not grow any taller than their distance from the building.”

Is that something to be worried about or are they just covering their arses?