I have an Astra J hatchback, 2015 reg, I think it is “pre facelift” but not sure.
It has slow punctures on both off side wheels


My tyre garage (Formula 1 Autos) told me that air is leaking from between the valve body and the alloy wheel seat.
They say that if I can get hold of replacement valves they will replace them. They say that this will not involve disturbing the TPMS.


Are they correct?
Is the TPMS separate from the valve on this car? All I can find are combined TPMS and valve