I can help you a little further, 854 Naval Air Squadron was disembarked to MONAB 1 at Nowra on May 18th as part of a new reserve Air Group (CAG)being formed there, No. 3 Carrier Air Group.854 Squadron disembarked from Illustrious to Nowra’s satellite airfield at Jervis Bay to become its first element.The CAG which comprised of No.s 854, 1843, and 1845 squadrons, was officially disbanded on October 24th No.s 854 & 1843 squadron personnel embarked in S.S.Stratheden for passage to UK, all aircraft were retained at Nowra.
As for your grandfather’s rate and trade of P.O (TY), this is causing me some problems.I have enquired about the (TY) suffix with my network of WW2 contacts and the only suggestion to be offered is that TY is an abbreviation for Temporary, inferring he was a Leading Hand filling a Petty Officers role.
DO you have his service records? Or any photographs of him in uniform?If you do have any of these perhaps you could e-mail me direct firstname.lastname@example.org and I will see if I can unearth more information.