As most have said above, if the surface has not been adequately prepped/cleaned properly before application, then it wont bond properly and you wont get the best from the product. Given the swirls are there, that may well be the case.
Russ Aston at Midlands Car Care is your man, he's invested a huge amount over the last few years in his business and covers all aspects of detailing/vehicle enhancement. I've met him and seen his work for my own eyes and I'd most certainly recommend him.
Not only will MCC lavish lots of care and attention to cleaning the car properly before application, they will reapply a glass coating for you (I know they use C-Quartz Finest which is one of the best in the business).
Yes it will cost, but you are safe in the knowledge that it will be done properly to a very high standard.