OK I gave up with Fusion 360. Good package, obviously excellent price (free) but also obviously not written by machinists - getting things working on my hardware was a nightmare.

I've bought CAMBAM and cannot praise it enough. Fairly basic, but very adequate drawing package but you can import models if you wish. But for my 4th axis they have a 'wrapper' plug in rather like CNCwrapper. It wasn't perfect (too many digits after the decimal point for my Heidenhain controller). I sent a message to the author and within 24 hours he had amended the plug in embedding controls to allow choice of not only the number of digits after the decimal point in the 'wrapped G code' but also allowing suppression of comments, which my controller had objected to. When it came to fine tuning my post processor, again lots of help from the CAMBAM forum resulting rapidly in a working solution.

Yes I'm a happy bunny :)