Several Junior players play within the CDCL. You may wish to contact your local club. There is also a club specifically for juniors based in Coventry.
Coventry Chess Academy, aimed at players in Years 1-6 at Cheylesmore Community Centre 10-12 on Saturday mornings. This is their website. https://coventrychessacademy.wordpress.com/
More information about the Cheylesmore Community Centre site: http://www.cheylesmorecentre.co.uk