Mal,
A Caution is a police record NOT a criminal conviction. So an enhanced CRB check will show it but employers should understand the circumstances and allow you to explain the reasons. When receiving the caution the duty police inspector would have expliained that you were admiting the offence and therefore the caution. Battery is the lowest form of assault and can be a scratch, push, slap etc. You don;t say how long ago this was as the longer time the better the employer will feel about employing you.
If enough evidence was available to caution it follows that you could have been prosecuted at court and then have a criminal conviction. So the police caution is a way of dealing with minor law breaks like your incident.
The caution cannot be removed and will always be on your police record, it is not a criminal conviction and if a job application states "do you have any criminal convictions' - you can answer no.
HOPE THIS HELPS
LawMan