The 'PhanDet' formed at Port Stanley with 9 jets in October 1982, soon to be replaced by 29 Sqn, 23 Sqn then replaced 29 Sqn in April 1983,,
TBH I don't remember it really working quite like that.......
As I recall it 29 Sqn effectively founded "Phandet" (having migrated in part from ASI) and ran it/manned it until the end of '82.
23 Sqn personnel started to replace them in Dec 82
and by Mid Jan 83 I'm pretty sure "Phandet" (for despite the change in personnel it was still known as such) was almost 100% 23 Sqn personnel, with a "rump" left back at Wattisham to keep the flag flying......a month or two later the axe fell at the UK end...
The 23 Squadron colour did indeed follow the troops down to the Falklands in Spring '83 and only then was the label "Phandet" dropped.
FWIW At pretty much the same time as the squadron colour went south some of us on 23 were heading back north to the UK....