I doubt he'll be unemployed for long and his pension will help cushion the blow.
In fact, of course, his position in the Civil Service would have been virtually untenable after such a public split. No matter where they put him his superiors, and, perhaps more importantly, his subordinates, wold jave been aware of it the whole time. As Sir Humphrey would say, "I'm not quire sure he's sound."
We have no way of knowing, but that wasn't really the problem with this man. He seemed to be incapable of accepting the status quo, and that prevented him from being efficient. He was an ardent Remain supporter, and appeared not to be able to adjust to the fact that we voted to leave.
Whether or not his point of view was right, his job was to assist the government. Instead, he decided to launch streams of critical emails, and in the end it was obvious that he would have to be gone before official negotiations started - he would have been a liability. Unfortunately, he couldn't do it gracefully; he had to fire parting shots, making sure they were leaked to the press.
Experience or no experience, we are certainly better off without him.
We need a representative that is an optimist and has a positive view in getting the best outcome, not a pessimist.
If Sir Tim Barrow pulls off a good result, his profile will hit the roof. He'll probably be the one ambassador of this country that many people will be able to name. I suspect he'll be constantly in the media, whether he wishes it or not.
This coming year or so will be huge in a political sense and for anyone interested, fascinating. History will be made. I for one (sad perhaps?) am looking forward to it.