Long waisted - need help dress searching for wedding

[SwivelHips]

/sigh/
DSS Wedding end of August and I have jack shit to wear. I tend to avoid dresses as I'm long waisted so never found one I really like.
Size 14 and I dress really casual now. I'll also have 3 yr old in tow so I'll be covered in all sorts.
I like some of the lk Bennett stuff but their dresses are now about 200'quid. When did that bloody happen. I used to shop in their pre kids.
Budget ideally less than 100 and I don't love my arms
Trouser suit?
TIA