It is well accepted that the pink sensor is unreliable and one of the main causes of F75 faults.
All of the advice is that they should always be changed because they are very likely to be the main cause of the F75 which you have been called for.
If you don't change it on your visit then you are likely to be recalled to the boiler and in my case that will be unpaid.
Tony
Recharged for a return visit then! Remind me tony what is your pricing structure I don't think you have mentioned it before!