'51' being the version of the EVE spreadsheet I've reached!
Following the conversion to Power Query all seemed well. There is a bug I created myself by deleting worksheets without disconnecting downloads on them, but that just requires pressing a button twice.
Meanwhile the devs have progressed from one API front end, CREST, to another, SWAGGER. Noticing that it had a useful price list I ventured into it armed only with my shaky knowledge of JSON and it was as tricky as I feared. Why is every entry called 'Record'? Much searching followed until I realised that the 'List to Table' button was the magic one.