@BarryCarlyon I’m sure you hear this multiple times, I do recognise the level of ranks you hold on these forums but you have fixed it!
So… Solution time ladies and gentlemen
Nothing was wrong with the hashing, hmac, secrets, it was indeed, the json_encode
I changed:
$body = json_encode($request->post());
to:
$body = $request->getContent(); // Subject to the fact you're using Laravel and the Illuminate Request class
This fired a response as expected!
Thank you ever so much @BarryCarlyon
P.S - The edit tag… I hate doing it too 
but its nicer than another reply!