Alan Willson was attacked by a gang of teenagers in Longcroft Park while rushing to defend his son on Easter Sunday.
Police confirmed on Tuesday (May 26), he remains in hospital in a ‘serious condition’.
Five teenage boys were initially arrested over the attack on suspicion of attempted murder and grievous bodily harm with intent, but were released under strict bail conditions.
And three of the boys were rearrested as part of the ongoing investigation last month. They were released on conditional bail while the Crown Prosecution Service considers all the evidence.
Police are keen to speak to anyone who saw any suspicious behaviour in the area around that time or who may have seen people running from the scene.
Anyone with information is asked to contact police online or by calling 101 quoting Operation Swallowtail.
Information can also be passed to police anonymously via the independent charity Crimestoppers online or by calling 0800 555 111.