I ended up changing the colours on this afterall! It did feel a little dull before... I was sort of going for an earthy look, but it was too earthy. I have a habit of making quite mucky looking artwork, I dunno if that's a fear of using brighter colours or just that I have a personal preference for duller tones.
Either way, I think this creamy background is off-white enough to be gentle on my muddy-loving eyes, but bright enough to not overwhelm the illustration now. And I've been staring at it for a few days and I still like this pallet. So I consider this fini! A4 prints are available from my Etsy, as well as handmade stickers, or there's vinyl machine cut ones available from Redbubble!