Some progress on this, managed to work out how everything will go together, just waiting on a new cutting disc for the grinder to arrive as the old item is beyond buggered with chunks missing.
Not the most complex of designs but it seems like it's going to work
Here's what the trailer looks like if anyone's interested. Not the prettiest of things but I'd rather be towing it rather than piling stuff onto the back of the Sinclair like I had to last summer.