I'm 40yo, 5,3", size 14. Church wedding followed by posh hotel reception. Some of the stuff I've seen people wear as wedding guests recently looks more like clubbing wear, I don't want any bodycon type stuff! 
These are some ive seen so far which I like.
monsoon
phase eight.
debenhams
The last one would be easier for accessories I guess. I'd like some sort of hat/fascinator and not seen any in the right shade of green for the first two.