Thanks guys, I appreciate your feedback. I showed it to my boyfriend and he said the same thing. So weirdly enough I started working on what that photomanipulated version looks like and then you posted it! Not as purple, but I've added some oposites to try and make it pop more, so hopefully I've helped improve it a bit.
With the colours I use, I need to keep working on them, but that's really the colour pallette that I want. I want that to be one of the themes in my work but I guess I just need to practice and experiment more with subtle blues or something to accentuate it. I totally agree about it all blending and going flat, so hopefully doing that and not being afraid of having bold shadows in my work might improve it all.
Thanks again for all your help! I'll repost asap.