Carter spent eight years in charge at Five Heads Park, taking them up from Division 1 of the Wessex League and establishing them in the top flight.
Deans were top of the Premier when Carter left to take over at Moneyfields almost six years ago to the day.
He returned twice with Moneys, for a 2-2 draw in March 2016 and a 2-0 win the following August when Steve Hutchings and Dan Woodward scored.
He hasn’t been back since, though, but gets his chance on Saturday as AFC Portchester visit in a rearranged Premier fixture.
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It will be the two clubs’ third meeting of 2021/22 with honours even so far - Portchy won 4-2 in August’s FA Cup tie and the Deans winning 3-1 in the league at the end of last month.
‘I put the foundations in place (at Horndean) and Birmy (Michael Birmingham) has carried it on,’ said Carter. ‘I basically ran the football side of things there for eight years - we were top of the league when I left, above Salisbury.
‘I brought the chairman in, and I brought in their main sponsor (Lee Jackson) just before I left.’
Horndean’s victory at the Royals on September 28 was one of six straight league wins they have rattled off. As has been the norm in recent seasons, they are the highest placed PO postcode club in the Wessex structure.
Portchester, down in 13th place, are 13 points behind the Deans with a game in hand. They will need to embark on a great winning run to hoist themselves into title or play-off contention.
‘Birmy’s had five years to put his team together, I’ve had two months of competitive football,’ said Carter. ‘It does take time.
‘People say we’ve got Southern League players, but we didn’t do particularly well in the Southern League in the last couple of years (at Moneyfields) because the budget got cut.
‘Yes we’ve got good players but some are getting used to this level, it’s different to the Southern League. The standard of refereeing is also different - I’m not knocking the refs, it’s just different.’
Carter added: ‘We’re not in the right position (in the league).
‘We’ve had a tough start - we’ll have played Horndean twice, Brockenhurst and Hamworthy. They’re the top three teams, and they’re a third of our fixtures!
‘We’ve lost to Hamworthy, Brockenhurst and Horndean and that means when we play them again we need to be better and we need to be taking points.’
Of the home loss to Horndean, Carter said: ‘We were punished for two mistakes just before half-time. It was all about who would make the first mistake, and that was us.’
Portchy have a full strength squad apart from defender Curt Da Costa, who could be out for four to six weeks with a knee complaint.
In contrast, Birmingham said he is down to the ‘bare bones’ in terms of players available.
The situation was not helped at Fareham in Tuesday’s Wessex League Cup loss where midfielders George Burgess (hairline shin fracture) and Zac Brownlie (cracked ribs) suffered injuries.
Regarding the 3-0 defeat at Cams Alders, the boss reported: ‘It was men against boys in both penalty boxes. In the middle third Horndean played the better football.
‘Fareham were a strong, physical side - 3-0 flattered them I thought, 2-0 would have been fairer. After the second goal our team were out on their feet - they had given everything against a powerful side, and they were powerful.
‘As I said to the players afterwards, the young boys have to understand they need to be fitter. If you are you can move the ball around better, you can be sharper - and you’ll be mentally sharper too.’
Previewing this weekend’s clash, Birmingham said: ‘People are writing Portchester off but they are capable of going 15-20 games unbeaten. Look at the squad they’ve got.
‘I’m down to the bare bones, I’m struggling, but if I have to roll every player off the pitch at the end and into the changing room having put in a quality shift, so be it.’