VintageTwisted,
I think if your new banner fits your style, it should be fine to change it. The only time I would advise against any major banner changes is if you are a super popular shop that has already built recognition based on photos, logos and your banner. However, for a smaller shop like yours, I don't think it will be a risk. I changed my banner, and since I had very few views, no one even noticed! Go for it!
Aman