Back to applying vinyl for anyone who wants to do it themselves.

I always use tack reducer, it temporarily delays the adhesive on the vinyl allowing graphic repositioning & a bubble free application.
I also recommend checking out youtube as there are some great tutorials on there.

I am no professional but i have used vinyl on a manner of classic vehicles to give dashboards wood effect, or temporary cheap chrome on bumbers (using heat to stretch and shrink vinyl around curve - that takes practice).
I have also applied large sheets to walls and windows which is easier then curve but a second pair of hands is vital I think.

Below is my preferred product but others are available.
https://www.grizzlybearonline.co.uk/vinyl-application-fluid/1-rapid-tack-pro-spray.html

From memory we used to apply vinyls to new coaches using just soap and water it gives you a bit of leeway to reposition before you squeegee out the water from behind

My bus number (if any): RML 2747