Detective Sergeant Westbury said: "Police received a report that a teenage boy and girl had been assaulted with a weapon whilst in the park by a man on Friday 26th August at around 5.30pm.
"Both the teenagers were taken to hospital for treatment to head injuries.
"We arrested a 23-year-old man yesterday, Wednesday 19th October, on suspicion of assault occasioning actual bodily harm and possession of an offensive weapon in a public place. He has since been released on police bail to allow for further police enquiries."
Detective Sergeant Westbury continued: "Our investigation into this unprovoked attack is ongoing and we are still appealing to the public to contact us with any information that may help. If you were in the area on that Friday afternoon and noticed anything suspicious please contact us on 101 quoting reference number 1488 26/08/22."