Need a dress for DS first Communion...

[ChippyDucks]

I need to find a dress for this occasion, but I don't want to look like I'm going to a wedding iyswim?
I've had a look but can't find something that will fit the bill...need some sort of sleeve (I don't do sleeveless), and that I can wear with existing heels, either black, navy or nude?

Has anyone seen anything remotely suitable? Ideally I'd like to stick to under £80.