If you have anything on there that wasn’t on there when the car left the factory, it’s a mod. If you didn’t declare it, then there’s the very real risk the insurance company could void your insurance. Admiral are particularly hot on this, too.
That said, if you didn’t hit a person or property then they’re unlikely to look into it too much so I wouldn’t worry about it right now. However, this is why I say to always declare everything, because the last thing you want to be worrying about after a crash is whether you’re actually insured or not!
I’m puzzled about the wrap though, that’s definitely something they want to know about so I’m very surprised that they didn’t care when you told them. Very odd indeed.