Help a desperate woman with summer office dressing, please.

[Thunderface]

I changed jobs in recent months and am now office based. I asked my line manager about dress code and she said just regular office wear. She dresses quite formally in my opinion and is usually in a suit and high heels.
I work in a different location and usually work alone so there is no example to follow. To make matters worse my office, and the building in general, is incredibly warm and that's something I can't change.
I'm short, size 18 and late 40s.
Trousers are very difficult to find for my height & size. I like dresses but can't wear heels and hate tights at this time of the year.
I'm really struggling. Any suggestions welcome.

Dresses, no tights and flats, sandals or wedges. If needed, keep a suit jacket on the back of your chair for meetings, unexpected visitors etc

Or a nice knee length a line skirt with a blouse or top

Agreed. Cool floaty dresses that finish midway between ankle and knee, but not sleeveless, with a jacket to smarten up if a meeting is scheduled. Flat but smart shoes. Bare legs if it's really hot by UK standards - high 20s or low 30s. Otherwise you can wear low denier knee-highs or thigh-highs without the uncomfortableness of tights. But tbh no point if you're usually the only person there and all meetings are by video call! Only if you have an external meeting in person.

@FirmlyRooted

Or a nice knee length a line skirt with a blouse or top

This would also work. Mid length skirt and a smart-casual blouse with short sleeves.