The Summer wedding outfit dilemma...

As a decidedly non-seasoned wedding goer, I don't have an on-hand wedding designated wardrobe, so when I do receive an invitation my mind often draws a blank as to what to wear to fit the occasion. Plus these days choosing an outfit isn't as straightforward as it used to be. Gone are the days of being certain that it'll be a traditional church service type affair.


I currently have the dilemma of choosing an outfit for a wedding party, which is the day after the actual wedding.  It's a barbecue do at a pub but we've been asked to dress in wedding attire. Sounds simple, but how wedding-ish should I go? 


My initial thought was that I should go for a lovely summery floral frock, gorgeous wedges & a corsage in my hair, but if I'm honest, I'm not really a feminine frock kind of girl. I'm not blowing my own trumpet, but I can do sophistication, it's just a shame that I don't get invited to any glam city weddings.


We attended a marquee in a field country wedding last summer, to which I wore a blue jersey grecian style maxi dress with a wide leather obi belt & accessorised with chunky turquoise jewellery & a feather headband. It just didn't feel right given the surroundings (& needless to say the outfit went onto Ebay). Everybody was floating around me in diaphanous tea dresses & Boden type bouquet floral shifts.


So my mission is to find something "suitable" for said impending July event whilst still retaining my own style...Any suggestions will be gratefully received!