I only go to weddings about once every 5 years or so... so I have NO idea what guests are supposed to wear, it is a minefield.
Our closest friend is getting married in April (still fairly chilly). It will be a civil ceremony in a hotel, reasonably informal I think (1 BM/MoH and 1 flowergirl -our DD) definitely not black tie or morning suits.
I am currently a 12, 5'0", not very toned atm (usually a 10 tbh). Too old for strapless (late 30s), and am quite norky (32 E) so need to be careful with top half.
I have no idea what colours suit me
; I like grey, navy, and black usually hair is non-descript brown and grey in a short layered bob, skin is pretty pale.
My day-to-day wear tends to be from Gap, M&S, White Company and a little select White Stuff/Fat Face.
I like this, but I'm not sure it's smart enough, though it is very 'me'- boring, plain, down-to-earth.
This is smarter but I'm not sure as it seems very low cut- will be below my breasts for sure. (v short back)
I am not sure if the print on this one would be too much for me, though it seems more weddingy.
I like the colours in this but not sure if it will be okay norkswise.
This is nice and simple but is it formal enough? And I would need something under that chest crossover...
Would love to splash out on something of this ilk but cannot really justify the cost, as cost per wear would still be about £200 after 5 years 
Any ideas please?
Oh- and I have 2 very small children, so ideally (ha ha) washable.