[Paul]

The fault indicator is showing fault but all tyre pressures are correct! What advice can you give please?

[olduser]

I think, what you are seeing is almost inevitable, it is very difficult to reliably measure tyre pressure on a moving wheel. I am surprised that they are included in the MOT.

I found these instructions on how to reset the system, which may resolve your problem;

"To relearn the TPMS on a Ford Fiesta, inflate all tires to the recommended pressure, turn the ignition to the OFF position, and then cycle the ignition from OFF to RUN three times, ending in the RUN position. After that, press the brake pedal, and follow the prompts to scan each tire sensor in the correct order until the training is complete."

Remembering recommended tyre pressures are for cold tyres.