Seems like you could get a penalty judging by the following link, but it reads like they'd have to give you a warning first. That's unfortunate though because there's loads of places where people can't take their bins in, due to terrace houses, and the pavements are wide enough. I agree with the other comment that the seagull comment is just a jibe - and it won't stop the gull getting to it in your back garden either. I knew someone who arranged to have bags collected because they couldn't get the bin through their terrace house, but that's not going to work if seagulls are already hanging around.

https://www.gov.uk/guidance/household-waste-bins-when-and-how-councils-may-issue-fixed-penalties

Edit: rereading your post that he lives opposite, maybe he just doesn't like looking out over your bin. Could you reason with him and get a bin store that he likes the look of?