Ok, so I should have said "this weekend my dragalong gets a hydraulically operated swinging back axle" , cause so far that's what's done. Not being able to find my 3/4" drill bit cost a lot of time looking everywhere and finding all sorts of lost treasure in the process. In the end I had to run with what I had at hand which was a 31/32" drill bit and a die grinder (which seemed to take forever to take .4mm off the radius) - that was for the ram pin brackets.
The whole process involved looking at what steel is on hand that preferably doesn't require cutting - got lucky with the pump bracket and the axle gussets - the gussets were a square of 5mm plate that had been cut with a thin disc about half depth across corners (someone must have changed their mind half cut??).
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