Weird work getting- what to wear?

[Allwelcone]

New job, nearly everyones 40's 50's as am i. Tomorrow I've been summoned to a 3 hour role play training session by line manager and CEO.
This is an opportunity, if I do well I will be given more responsibility.
WHAT DO I WEAR? dress up or down?
it's training but role playing external facing project to clients.
The 2 men I'm meeting wear trad tailored trousers and jackets.

Smart trousers, blouse
Take blazer to throw on if you want to/ feel the need to look smarter.

@springcantcome2soon thank you, I might freeze though! Oh yes...blazer...Will see what I have in the ole armoire.
Was gonna go with a dress....