Nah I just meant that while Affinity is great, for an open source project it's best to use open source software. That way you can easily share the core files in a way that are editable to anyone.
... Unless .svg actually does that for vector things, in that case I wouldn't really need to learn inkscape again.
ETA Anyway, I'll get in touch whenever I actually need the help (and I'm pretty sure I will).