Hi there and welcome from another newcomer.
I am miles further south than you, but the old name of my house meant wind hill, and it was well named. I wanted a polytunnel and after research also went for Northern and it has been very good. Put up without professional help nearly 20 years ago. No concreting etc. It has had 3 covers in that time, but really only though mistakes.
The first one I didn't use hot tape, and also used binder twine to tie thinks to the supports which damaged the cover. The second one I thought a builder would do a good job, but it was a loose as an old carrier bag and damaged quickly. This one has been on for around 5 years, and looks to have a good few years left.
I got the replacement cover from LBS who are very helpful
All the best
Sue
Dark Brown Eggs