The Fatty has bern laid up for three months with a time consuming repair.

On collection, it reported a TPMS system fault. It was reset, but it returned. Would this photo suggest that three TPMS valves have died during lay-up, or something else?

Anyone?

There is a section in the workshop manual about TPMS its section 204-04 wheels and tyres
Check and clear any DTC.
It is not possible to have a TPMS fault without a DTC being set.
There are lists of codes and what c&e they have.

Check car is not in shipping mode is one of the checks in the manual, also after 6 Years and more it states the sensor battery can fail on wheel sensor. 2018 SE SDV8 4.4 Byron Blue

If car been dormant for number of weeks, the sensor to save power will go to sleep. Once start driving it should wake them up. As mentioned it would normally put DTC in, worth checking and deleting, run car for few days and see if fault returns. If you have or can find some one with equipment ( does not need to LR) you can “ ping “ the sensors to wake them up. I have had success doing this before.

Failing that the batteries may have just died in the sensors. Only repair is to replace the dead sensors. You don’t need LR sensors, as good quality A/M will work.
you can clone them off original number (which is on the side of sensor once tyre removed) or if manage to “ping” you should be able to obtain the code that way to clone sensor. Failing that you can program new sensors to car.
Sorry maybe all sounds bit complicated but pretty straight forward to do , what ever route needed.
Hope it helps