Please help! What to wear to 70th birthday meal?

[EssexLioness]

Hi, my dad is 70 in a few weeks. He wants Sunday lunch at a hotel, near him. The hotel is nice but not super posh. There will be around 20 of us including lots of people I don’t know.
I am 44, 5ft 4in, curvy size 12 with a large ish tummy/ hips. I have no idea what to wear! I feel like jeans would be too casual but don’t want to go too dressy. I was thinking maybe a nice top and trousers/ chinos? I have several jumpers and accessories which look good but need something to go with them. I don’t do black, was thinking maybe dark grey, and don’t want to look like I am wearing workwear type trousers, but also prefer straight/ wide leg.
I am clueless re these things but really want to look nice as it’s a special occasion. I guess I’m looking for something smart casual.
Would love some ideas, and links would be amazing if possible too!

I do have a nice navy wrap dress too, but I don’t know what to wear with it! I only wear flat shoes. I have knee high brown boots but think that might be a bit dated 🤔 Also concerned it might be too dressy as it’s quite a casual area. My sister and partner live in jeans so won’t be too dressed up, so don’t want to look out of place.

I was about to say wrap dress. That and brown knee boots sound good to me, classic (it’s a 70 year old’s birthday) and like you!ve made an effort without being too dressy.

Thank you @Luredbyapomegranate. The dress is lovely but I wasn’t sure what to pair it with so haven’t actually worn it yet (bought a couple of months ago).

The dress comes to the top of the knee, and boots to the bottom of knee so will need tights or something too. Would nude tights work do you think?

The wrap dress sounds lovely but I'd be worried knee high boots would be hot and uncomfortable sitting for a meal. I'd go with an ankle boot. Both with opaque tights at this time of year.

Thank you, good point about being too warm but I feel the cold a lot so this is actually a bonus for me!
I tried the dress on earlier with the boots and they look really nice together. Not sure why I was convinced they wouldn’t.
So outfit sorted, just need to play with accessories. I might try with ankle boots anyway to see which I prefer

That’s good news!