The short answer is that you have to comply with the requirements of the order as directed by your supervising probation officer. Whilst this is not a definitive document, the link below shows the London probabtion service's policy on travelling abroad:
http://hub.unlock.org.uk/wp-content/uploads/NPS-circular-01-2011-travel-abroad.pdf
You will note:
"To ensure that offenders subject to probation supervision while on a community order or licence are effectively managed throughout their order, temporary travel outside of the United Kingdom should not be granted other than in very limited and exceptional circumstances."
and:
"Requests for travel for business, recreational or holiday purposes will not of themselves be considered “exceptional circumstances” but each request
must be properly assessed on its own merits"
If you cannot reach agreement with your supervising officer that yours are "exceptional circumstances" you will need to go back to the court that handed down the sentence and have the issue ruled on by by the magistrates. It is likely the probabtion service will oppose your application and you may have a fight on your hands.