hope you managed to get things sorted.
I have very similar issues with Ben 7 and Harry 1 both been 'done'
Ben hated everything about Harry when he arrived 5 months ago, however the only thing that is really an issue now is toys/playing. like Bayliss Ben develops a red mist which makes him want to flatten Harry whenever Harry tries to initiate play.
I took all toys out of the house to avoid confrontation then slowly reintroduced one toy into the house for a short time. We have got to the stage where Ben doesn't go ballistic if Harry picks it up and carries it round but he starts to get wound up if Harry tries to play. its worse if Ben has the toy and Harry wants to join in.
Outside is a bit more tricky. if Ben is running and Harry runs up and tries to start a game things get nasty, I usually do a whistle recall as soon as things start to look a bit dodgy. I made the mistake of taking a ball thrower for the first time last week and it was horrendus Ben was so wound up that Harry only had to look at him and Ben got quite nasty.
I will be really interested to hear how things go for you and how you manage to make progress, any tips about what works greatfully recieved
Bens mum