Hi there, HNY from Victoria. My old apartment garage was filled with storage solutions from innovative owners!
I would write to your OC and ask permission. I would have thought an email was enough. If you assure the committee that a qualified and insured tradesperson would install the fixtures and that they would be in keeping with the look and quality of the surroundings, perhaps providing them with a picture of the product you have in mind and indicate what would need to happen to the car park e.g. where concrete drilling will be required, and an assurance that the fixture or the kayaks won’t affect any neighbouring car parks, then I can’t see what the problem is. If I were on the committee, I’d agree to that if it were restricted to your car park space and professionally installed. There are some pretty nifty over-bonnet solutions out there that make good use of that space.
Hope this helps encourage you!