I'll stick to the 'holidays' bit:
Assuming that you're a UK (or other EU) citizen you have the right to travel to, work in and live in any of the 27 member states. You can't (except under very exceptional circumstances) be banned from entering, even if you've got multiple convictions for GBH, drug-dealing, bank robberies and serious sexual assaults. You've got just as much right to travel to Italy or Latvia as you have to Ipswich or Luton.
The vast majority of non-EU countries place no restrictions on UK citizens entering for the purpose of tourism. Even those countries which require you to obtain a visa hardly ever ask any questions about criminal convictions. The only countries I can think of which do ask about criminal convictions are the USA and Australia. (Canada has a theoretical bar upon anyone with a criminal conviction entering their country but they don't actually ask any questions or require a visa). The US Embassy requires anyone who has ever been arrested (even if totally innocent) or who admits to having committed an offence (e.g. by accepting a caution) to apply for a visa but 'common assault' is not a crime of 'moral turpitude' and doesn't create an automatic bar to entry.
So neither a conviction or a caution is likely to have any effect whatsoever on your future holiday plans (except that you'd have to apply for a visa, rather than travel visa-free, for entry to the USA).
Chris