NJ's link seems to have gone AWOL. I'm guessing that this is the one he intended to post:
https://www.sentencingcouncil.org.uk/offences/magistrates-court/item/affray/
(Somewhat oddly, there seems to be no Crown Court sentencing guideline available).
Based upon reading court reports for around half a century (and having done a small amount of court reporting myself), I know that judges don't rush to send first-time offenders to prison. Any custodial sentence which is passed is likely to be less than 2 years, meaning that the judge can consider suspending it. A first-time offender, expressing remorse, in regular employment and with a secure family background stands a reasonable chance of seeing any custodial sentence suspended.