Thanks a lot Maninashed. It's no biggie for me to use Graphic instead of Affinity - was just surprised the more "powerful" of the 2 can't upload a gradient to GTS. have tried text and works well (as long as you remember to convert to curves!) but nothing else so far.
I haven't tried it the other way around - even if it worked it would be more effort than just using Graphic.
Here's the Affinity file for a plain mid-blue square, no gradient, no stroke:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "
http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="100%" height="100%" viewBox="0 0 825 825" version="1.1" xmlns="
http://www.w3.org/2000/svg" xmlns:xlink="
http://www.w3.org/1999/xlink" xml:space="preserve" xmlns:serif="
http://www.serif.com/" style="fill-rule:evenodd;clip-rule:evenodd;stroke-linejoin:round;stroke-miterlimit:2;">
<g transform="matrix(1,0,0,1,-642.875,-568.912)">
<rect x="642.875" y="568.912" width="824.288" height="824.288" style="fill:rgb(0,94,255);"/>
</g>
</svg>
There are 4 options when exporting to SVG - For export (which is the one above), for print, for web and flatten.
Thanks again.
EDIT - three of the four squares successfully uploaded to GTS and displayed fine in decals library on the PS4. The "flatten" version wouldn't upload as it was an invalid SVG format.