Great tips, thanks, and I'd be on them if I was in a garage/workshop. My own and site limitations lead me to the capable services of a local engineers.
I think I'll put it back together and gingerly make my way the 3.5 miles to their workshop, just in case it needs extra heat/welding on nuts/or any other sorcery! If it's straightforward, it won't take them long, and if it's complex they'll have the resources to work round issues.
