Trouble with geojson

[dayres66]

Hi, I am using Icon Map with a geojson layer for postcode districts, it works fine for most that I downloaded and store in Azure.

2 of the files would not work so I used Mapshaper to simplify, it turned them into json not geojson but hey presto, it works

I have one final Postcode area (WC) that no matter what I do will not render on the Icon Map, everything looks fine in maplayer, geojson.io but just not in Power BI. I am hoping someone can point me in the right direction. I have researched everywhere I can think of, but have hit a blank. I can add a pbix file if necessary which shows they all work other than WC postcode area, really quite bizarre!!

Many thanks

Dave