Research and hope.

After not being able to sleep most of the night from worrying if we'll ever be ready to move in time, I decided to look back on chases 'acting out' and have found it's been happening roughly every two weeks ish.

There were a couple of posts on Google about Staffies and staffy crosses having the same issue with no obvious trigger for the behaviour.

One post I could have written myself, it was almost identical to what we're getting from Chase!
The owner sought advice from a qualified trainer (which is what's in place once we've moved) and they found it was a nervous reaction from the dog and over excitement causing a 'toddler supermarket tantrum' style behaviour.
The dog eventually outgrew and overcame it's nerves and they never saw the behaviour again so I have all hope for Chase

Also it may be surges of hormones still and his little body still settling after the neutering which is making him uneasy at times.
It has only been happening since he was neutered!

Overall I'm happy we can work through his 'tantrums' with his trainer as that's his main issue now. Everything else has somewhat resolved itself

I'm not giving up on him!

That's really great news, I took so much comfort from finding other people's dogs doing the same thing as mine especially when it gives reasoning behind the behaviour. Hope the trainer is a good fit with your lad and fingers crossed for the moving house too.

Never give up on him, he is doing so well & a good trainer will complete the good work you have been doing with him

He hasn't had another tantrum since those two days.
We'll be meeting his trainer next week to set up a training plan for him.

I'm still not all the way packed up ... Aaaargh!