They know their stock and they usually just want to help you buy something you’ll be happy with.
As well as this, they want a sale/
Sometimes I carry some pictures of myself as Wanda.
It may surprise you to know, but honestly, I get nothing but good reactions.
I’ve shopped for some sandals recently in Next whilst in male mode.
I ended up having a good chat about what I needed to the sales staff
The girls were friendly and helpful.
So bearing this in mind, your best bet is to go for it.
Good luck with it all.