I raised this problem with Wix and below is their unbelievalbe response:
'Please note that in case you want to create an extended multistage form, you would need to create it from scratch using Input Elements and Velo code.
To do so, remove the Wix Forms element and start adding the relevant elements to your page. ’
I’ve put in a huge amount of hours in designing this multistage form, is it really impossible to get around this problem, or are they too inept to bother offering a solution? If anyone can please tell me if I’m expecting too much?