Conversation so far:
When did Tom Simpson move to Brittany?
Tom Simpson moved to Brittany in April of 1959.
Why did Tom Simpson move to Brittany?
Tom Simpson's National Service papers were delivered. Although willing to serve before his move to France, he feared the call-up would put his potential career at risk.
What did Tom Simpson do once he moved to Brittany?
Tom Simpson applied to local cycling clubs, and joined Club Olympique Briochin, racing with an independent (semi-professional) licence from the British Cycling Federation.

Question: How long did he race in Club Olympique?
Self-contained rewrite: How long did Tom Simpson race in the Club Olympique?