Wedding Outfit Challenge: must go well with wellies!

[FGM]

My friends are getting married this July: the wedding will take place in a little country church, followed by a big reception party in a neighbour's field.

Rather than an inside sit-down wedding breakfast there will be food and drink in a big marquee, bales of straw etc.

We have been advised the bring a change of footwear in case it gets muddy (rains the day before).

I'm thinking:-
I need something relatively easy care
Nice shoes for church
Wellies- I have shortish aubergine Hunters
Something warm- could get chilly (nice cardi?)

I'd love something like this but in cotton. Any one seen something out there?

How about on the same website the everyday cotton silk dress? Or they do the same one in a linen/cotton? I bought it and it is really lovely. But I think your ideas are perfect and would definitely assume the worst and go for a nice cardy and also coat/umbrella at hand just in case. If you are young(ish!) could you go for a stylish country bumpkin type straw hat with real flowers or ribbons?