Most hairdressing wholesalers offer training sessions in bridal styling/hair up.
However, I think it’s one of those skills that if you have some natural creativity, you can master by following YouTube tutorials and practicing on a good quality training head. Sibel and Pivot Point make good quality higher density training heads that are perfect for practicing on.
Were you looking for someone to come into the salon to train a group of staff?
When I did the basic hair up unit in level 2 at college, we were very lucky to have a talented and award winning bridal stylist come into college and give us additional training. That was in the south west UK so it might be worth googling Professional bridal stylists and see if any are willing to offer 1:1 training?