Help with smart clothes please!

[Raisinandcheese]

I Am heading to a corporate type event on Saturday.
I am self employed and work from home, and do not possess any smart clothes.
I’m a kind of sundress or jeans person.
I am 5’9” tall, size 16/18 (depending where you buy. Boden is 16, next is 18 for most things bar tops when next is 16 too).
I am not a wall flower, have bright blue hair and I’m in my mid 50’s. So, therefore also nothing that is too hot!
But, I really need help with an outfit.
I do own some smart ish jackets, but I can’t do heels. I do possess some coloured trainers, and a variety of sandals but can’t wear most shoes.
I also only have 1 smart bag, which is blue so may or may not go with any new clothes I need!
It is an outdoor event, too. I think the weather is looking warm and dry, so that is probably good!
I mostly like bright colours, but appreciate these may be unsuitable for corporate events,but I can’t wear black, brown or anything too dark as it absolutely drains my complexion.
So, help, please and with online stores who can deliver by Friday. I won’t get time to visit any actual shops in person.
Thank you!

Hiya this site has lists of stuff from a few different sites which might be suitable for an office, loads of different styles and I'm not sure about delivery but might give you an idea
www.pocketsforwomen.co.uk/category/go-to-the-office-with-pockets

@Raisinandcheese
Corporate evening events are likely to be less formal. You won’t need a jacket unless you choose a trouser suit. I think a nice dress is just fine and you might even wear it again! These are M&S.

Thanks.
@TizerorFizz it’s a day time event.
I do have a couple of phase eight dresses, which are abit smarter, would they likely be ok?
@Sheffieldissunny thanks, there’s quite a lot on there, but still not sure how smart I need to be?!

@Raisinandcheese Oh yeah sorry not actually been to a corporate event before so can't help on the actual styling 😳

As @TizerorFizz

Sorry cut off halfway through! But was saying as @TizerorFizz says nice dress should be fine

All the M&S dresses are perfect for day wear. Sorry I misread your first post @Raisinandcheese

What is your budget?

@TizerorFizz
thanks.
@ThreeB I usually buy used, charity or Vinted, ebay and so on! So, buying new is abit of a shock, but needs must. So, I would say around £80 for a dress, and £50 for footwear if I needed, and £50 for anything else.
Am abit flexible, around the numbers though.

I'd have a look at the phase eight ones you have. Can you rehash the look in any way?

None of the M&S dresses are £80. They have had a very good range this year at under £40. I’ve bought several: I like cotton. I wore one to a VERY expensive Michelin starred restaurant. I own the black one and you can dress it up fairly easily. Look at a rafia clutch bag and flat shoes. M&S do wide fit flat pumps. Easy to wear! By the way, casual is far more common these days. All the dresses I pictured work with flat pumps. We all need to be comfortable and well turned out!

@declutteringmymind I probably could, though being fairly clueless in the world of smart, I’m not sure what I need, although a couple I do have jackets that go with them.
@TizerorFizz thanks, I will have a good look, as m and s usually deliver quickly, too.