If you're on probation, then it's going to be hard to get permission. If you're on a community order, then it would interfere with your supervision, so it would be easier to wait until the order ends. If you're on licence, then not going abroad without permission will be a standard condition, and permission will be hard to get unless you're actually from the country where you want to go. There is some information about this on the Unlock website here
, which includes settling abroad. The relevant Probation Instruction is PI 07/2015, which you can find here
. If you read through that, it should show you what they are looking for, so that you can sort out evidence and arguments to convince them. Even so, don't forget that they are starting from a position of saying no, so you'll have some serious convincing to do....
As Chris Stacey said: Although its not formally part of the sentence that is handed down in court, the criminal record that someone comes away with effectively becomes a second sentence, which can have a long-lasting, if not lifelong, impact.