Not going to defend the railway operators but you are travelling at peak hours. Ticket to Sheffield was £56.70 return (did include senior rail card). If it's possible, why not organize the meeting for later in the day?
Firstly, it wasn't quite obvious as the OP stated he was on a different train. That said, the organisation at St Pancras was useless. On Saturday we were being told to queue for the 17:02 behind people that were queuing for the 17:30. Because I complained we were able to go to the front and...