Once an injunction is served, it is effective immediately. After service, not adhering to, or breaching the injunction, could be considered an arrestable offence. The specifics of the rules of the injunction should be detailed in the paperwork, which you should have a copy of, to double check.
Do your best to get a power of arrest added. It means the police can intervene and arrest him otherwise it’s a civil matter and back to court which simply retraumatises and costs x ring Righs of Women for free legal advice and contact your local women’s aid and victim support who may have funding and can support you x