As Eddies states, 'assault by beating' is an alternative wording to 'common assault' and, as such, is an offence contrary to Section 39 of the Criminal Justice Act 1988.
While it can theoretically carry a prison sentence (of up to 6 months), that only happens very rarely because magistrates can't send a Section 39 offender to prison unless they view the offence as falling into the upper end of 'Category 1'. That would require both 'culpability' and 'harm' to be seen as falling into the 'higher' category (e.g. where the offender had deliberately sought out a vulnerable person to attack them, leaving them greatly distressed for a long period of time).
Most Section 39 offences fall into Category 3 or 2, meaning that a fine or community order would be the eventual outcome.
See pages 189 to 192 here to read exactly what the magistrates will have in front of them when considering their sentence:
https://www.sentencingcouncil.org.uk/wp-content/uploads/MCSG-April-2017-FINAL-2.pdf