In 2048, George tried asking Dr. Patricia Audley what happened to Polly when she didn't come home at the end of term. She initially pretended that Polly left, but George said there was no record of Polly having used any public transport system — and there was no way his daughter could have walked from Antarctica to New Zealand. Audley eventually admitted that Polly had joined the university's classified Project Sub-Zero.
After explaining his story to the Twelfth Doctor and Clara Oswald, George died when the helicopter in which he was travelling came under attack by crazed seagulls and crashed, killing all on board. (COMIC: Blood and Ice)