Hi,to cut a long story short - though I do love to make a short story long so bear with me while I try!

My 8 yo CKCS rescue has been going to a paid daytime carer due to his Separation Anxiety/noise reg neighbours for nearly a year now.
She is very good,adopts the positive re-inforcement strategy for the most part (odd rattling of stone can,squirty air collar! ). Titch has always been happy there.....long 2 hour off lead walks....lots of socialisation...within a controlled environment.....
Although separation from Titch since has been more stressful for him re: dribbling excessively when we're gone & key woofing points i.e. getting a particular uniform on,reaching for keys etc which he never used to do pre-carer (not left on own as much then I can suppose - worsened the SA - opposite of what I was trying to achieve!?)

I was offered a couple of months ago through a chance encounter FREE! dog care!
A neighbour just a stones throw from my house said they'd love to have him when I'm not home....I took them up on it...they have a darling Staffordshire Bull Terrier with a heart of gold & a temperament of a saint.
It worked so well for a while though they did feed Titch a mite too much - liked to show their love through food (Titch commonly gets 2 small square protein filled senior directed dry meals per day,a couple of small treats & a lamb bone once a week) They were giving him access to the other dogs breakfast/dinner....human food titbits,treats as a constant drill throughout the day! Titch probably thought for a while...'yeah sweetie shop,mine mine mine!'

It all went skew whiff however when Titch & the resident dog came to blows

They had a really nasty fight (as I am informed as I was at work)
Apparently Titch started it....say what! ( I asked - they swore no food was around at the time!)
In my experience of Titch (since he was 10 months old) I have not,& no-one who has ever come into contact with Titch,including paid carer,has ever seen anything remotely leading up to this with him :-O

Ok,scenario over,drama quieted - neither dog was hurt - perhaps due to free carer being on the ball & breaking it up asap??

Where to go from here? Free carer wants to try any & every poss avenue to make it work. I was resigned to the 'It didnt work,hey-ho immediate neighbours will have to put up with the noise the rest of the week whilst I take Titch to paid carers only 2 days'

The suggestion has been a muzzle re: both parties but that can only be a temporary solution perhaps to integrate them both again? Theres no way I would be up for a muzzle on Titch for like 9 hours 3 days a week :-(
Thats trying to treat the symptoms not the problem anyhow huh & give Titch negative thoughts?

There is so much more I can input as to the situation but am trying to cut a long story short!

Titch has shown no aggression other than a warning snap here & there thoughout the years....its just not in his disposition :-/

What to do next?

Worried & dont wanna inadvertently do the wrong thing.

Dont wanna reinforce the aggression by forcing him into a situation he may not be comfortable with

Do Titch & the free carers dog (3 yo male) have a future being friends? Is it attainable? How?

Thank you for reading,am so stuck,I did consider myself quite dog worldly! Would love opinions & suggestions on this one though. Aggression is not a new concept to me though with this dog it is & wanna speak in Titch's language? x