I might have another solution.
I recently had to change one front tyre, because of a serious cut in the tread, probably caused by a pothole.
This change has since caused the TPWS to activate several times, I guess due to the differing tread depth between the left and right hand tyres, although only about 1.5 mm.
Yesterday on my usual trip 'oop north ', a 240 mile round trip, the TPWS activated again, early on in the journey on the M42.
I stopped at the next services and checked TP and reset the system.
It did not activate again during the next 200+ miles.
Could it be that, resetting the TPWS on straight motorway type roads, rather than twisty urban roads has made the difference?
Certainly it is logical to think that this is so, time will tell!!