Unsure which way to jump with this. I'm a size 20 18 on a good day and apple shaped. It may be casual but IMO people will be at very much the formal/stylish end of casual. I have a dress I could wear, but it could be described as 'fun' and might as well have the shop of origin written across it in bright red letters. I would rather have something a bit more mature. I have a bit more money than I used to but would still rather go ebay or something, but really unsure which way to go for this - like a lot of style clueless people, I have some black work trousers and some evening stuff but almost nothing in between except jeans. Any help gratefully received!