Further to my earlier post I can confirm that TfL customer services have resolved all the issues with the faulty reader at George Street tram stop. The reader is now working and they have worked to refund anyone charged an incomplete rail fare at Wimbledon as well as anyone who received a revenue check which could have been down to the faulty reader.
They’ve also provided some screenshots demonstrating how to raise an issue with them from the online journey history. I’ll be adding these to this site shortly.