Plus-ish sized girls suit

[IHE]

Single dad, helping 16yr old daughter shop for "business suit" for 6th form.
She's probably about 2 to 3st over weight and is quite body conscious so definitely wants trousers.
Any suggestions for good shops to point her at?

what dress size is she? Does she have to have a jacket or would smart trousers and a top work?

I'm not sure what size she is. (It's a long story.)
Smart trousers and a jacket would work. She mentioned trying the boys'/men's dept for trousers - I'm just a bit skeptical that the shape would work for her.

The boys department would probably be the wrong fit.
You need to find out what size she is, eg 16? maybe. M&S perhaps? She can let her fingers do the walking before visiting to try on.

Have a look at George at Asda online. They do sixth form outfits...and seem to have a decent array of sizes

Teen DD wears adult trousers from Next for school - she's not plus sized but I am and I have some nice blazers from there too, so might offer a good amount of choice.

Don’t go shopping in the men’s department, the fit will be spectacularly wrong particularly on someone who’s overweight! Men don’t have curves (hips / bum / boobs) and are generally broader in the shoulders and slimmer in the waist so anything that “fits” will be baggy in all the wrong places and make her look bigger.
next, M&S would be good starting points. Make sure the trousers are machine washable rather than dry clean. Sainsbury’s also has some decent stuff at good prices and they do bigger sizes. She needs to take whichever shoes she’ll be wearing with her to try things on as they’ll affect how trousers hang around the bottom. Also, don’t rule out getting things altered to make them fit better.

When I was in sixth form we all got our suits from Next, George (Asda) or M&S women's departments. I'd add Sainsbury's to that list now as they do nice quality basic clothes at decent prices.

Personally I'd start with Next as they have a good range of tall and petite clothing and their website clearly marks which jackets are available as suits.

You need to work out what size she is. She must know?

Unless you are able to buy a load of options to try at home, I think you need to head to a good shopping centre.

Id probably try John Lewis, Next, H&M. It’s not something I’ve looked for though so could be way off the mark.

Thanks for the advice on which retailers.
I assumed she was only talking about men's for trousers and I was always skeptical she'd find anything the right shape even for that.
We'll see.