V. sorry ronald no offence intended. Nothing personal .
It's just that I'm 'plus size' myself and so I'm afraid I probably tend to be much better at knowing what I don't like (usually anything that 'specialist plus size' and/or downmarket retailers like Marisota think is all right for fat people) than making constructive suggestions for what I do.
Also, I do genuinely think the trousers and jacket look can be frumpy and aging on big women - and it's a pity to cover legs if they're good.
Likewise, I like some animal prints - have some gorgeous accessories in them, eg from L K Bennett - but not for whole garments in cheap looking material.
I do know that's not much help to the OP.
Fwiw, I personally buy a lot from Boden, choosing carefully. Their sizing varies a lot but they go up to 22 and some items are generous. Think it would be worth OP at least browsing their site.
For special occasions, as I mentioned I go to Carolyn de la Drapiere but first I'm close to her workshop ( S W London) so can easily pop in to discuss and get her to make something personalised for me and second she's pricy (over £200).
My other source for dressy stuff is Marina Rinaldi but that's also mega pricy.
Think Navabi site worth a look, though have so far only bought a jumper from them.
Will have a look online around tomorrow and try to be more constructive.