Help! Overseas wedding guest PANIC

[sparechange]

Backstory: I'm the guest at a wedding overseas in a few weeks. The area is having unusually wet weather, and instead of the lovely hot temps we were expecting (and had bought outfits for), we have been warned it is currently thunderstorms and heavy rain, interspersed with very humid heat.

Added into the mix, I'm a stone more than I should be after a miscarriage, and the area is malarial, so I want to keep fairly covered up, especially my arms.

And I'm doing a reading, so I need to look smart, but can't look remotely bridesmaid-y (it is still a traditional white wedding, despite the location...)

I'm having a dress wobble. I haven't really worked out how to dress for my current shape, which is all hips, arse and boobs, and the things that my eye is drawn to just won't suit me at the moment. I am a 12/14 and 5'5"

In my head, I want to wear something like this
Or this but I think they will swamp me.

Oh, and what the HECK do I do for shoes? Wedges? Flats?

Budget would be about £100 each for dress and shoes, but could stretch to more for something lovely