Thank you Jon, I'm amazed to receive such positive feedback and I'm thrilled you like Marcus.
You're spot on - I do visualise what's happening and then write it down. I've just come from Rebecca Horsfall's 'Show Don't Tell' webinar where she said visualising was great - but maybe not to this extent! I will certainly try to let the reader fill in more of the scene themselves.
I have lots of homework now from all these helpful comments, and will try to tread the right balance when making my edits. I'm excited to see how it turns out though, I've been staring at this same draft for longer than I'll care to admit.
Thanks again for taking the time to read and critique, it's much appreciated!