This thread is eye opening!
I do not work in the UK & do not work in a corporate sector. However I am very senior, Director level, in a creative sector & I have never worn anything like those dresses. Ever. They are incredibly dated to me. I'm 53.
OP I have worked in Australia & I think the climate influences so much there. UK posters will not necessarily have that experience.
I would look at sites like ME+EM for inspiration with a little more 'edge' than most of what's been recommended here.
Good luck- it'll be a culture shock!