Re-bonding...

Hi everyone,
So I'll introduce all my buns.
First we have Hooch and Chewy, both neutered males, have adored each other since day one and never had one fight. They live in the conservatory.

Binky is a mummy's boy. Had him from 6 weeks and nursed him through stasis at 7 weeks. Lived alone, tried about a year ago to introduce him to hooch and chewy, separated them after ten seconds and never again!

Arnie is our new addition, when we knew Binky had been a bachelor too long. Love at first sight despite them being both males. Lived happily together for a couple of weeks. Then...

First hooch darted into lounge, from conservatory when we didn't shut door quickly enough (he's a little sod and will often try his luck despite having a massive room and lots of toys!!). Him and Arnie fought briefly, no damage just fur pulling.Binky wasn't in room at the time.

Next night: hooch again broke in. Feel so guilty we didn't learn our lesson and just use other door to the room. Him and binky fought, Arnie not in room. Neither hurt, although binky was limping a bit, on examination hooch had pulled fur out by bum. Bit of metacam and lots of TLC and he was fine an hour later, so we brought him upstairs to bed and Arnie as we normally did.
At 6am we were woken by them fighting. Fur everywhere. Separated them immediately and kept them apart for a few hours.
Have been trying rebonding since, 5 minute bursts when I can every day on neutral territory. Stressed them by going in car in carrier together. They groom each other, eat by each other, never lasts more than 5 minutes until they start circling and nipping.

Have considered getting a stair gate covered with chicken wire and keeping them both upstairs with this separating them. Presently we're one up, one down and swapping every other day so they can still smell each other when apart. Been doing this for about a week.

Would appreciate advice. They were so happy together and I'm prepared to stick at it for however long it takes, but want to do it properly. Convinced they now think the other is hooch!!
Thanks in advance

Can I just check I am reading this correctly...

Hooch and Chewy live together

Binky and Arnie live together

Hooch broke into Binky and Arnies space and fought with Arnie on one occasion and Binky the other

Which pair is fighting?

If it is Binky and Arnie I imagine it is a bit of stress and referred aggression - are they able to smell Hooch?

Hi, yes hooch and chewy live together, Binky and Arnie are fighting. When one of them is downstairs they are, we're swapping them between upstairs and downstairs at the moment. Is it worth keeping them both upstairs and separate for now do you think?

When are they fighting - only when they can see/smell hooch?

I'm letting them meet in neutral territory where none of them have been before (ie my bathroom!) otherwise they're separate. When they meet they're fine for a few minutes, then start circling/ nipping ��

You need to start from scratch. I would put both in a small neutral area and gradually increase space over a period of time. Personally I would try and make it so that this pair cannot see of smell your other pair as you will probably find referred aggression is a continuous problem. Basically they get frustrated that the cannot get at the bunny (hooch) so take it out on each other.

Thank you, have moved them both upstairs today with a stair gate separating them so neither can see Hooch, starting their meetings again in a couple of days when they've had chance to get used to their surroundings and each other's smell again. Thank you again for the advice, fingers crossed we can get back to being friends again!