John was part of our 1955 title-winning team, and confirmed himself as 'proper Chels' by managing Coventry to an FA Cup Final win over Tottenham in 1987.
Quick bit of research to answer my own question ... and this is how the 1954/55 squad has played out:
Frank Blunstone (23 starts) and Alan Dicks (1 start) are the two guys left that actually featured in the team rather than the squad. 7 left of the total squad ...
All subject to the usual google/wikipedia caveats etc etc
John Sillett was a squad member but didn't actually make any appearances in the league that season.
It's great to look back on games and trophies won by the team and for John to be part of our first title winning squad is a great honour. Not often I praise teams other than Chelsea and Rangers for winning trophies but Coventry City beating Spurs in the 1987 FA Cup Final was a great day.