Exemption is the method of choice. But on the phone, they will certainly not wink at you as if they would approve it. They will only tell you whether they will examine it (neutral) or reject it outright. But authorities are usually nicer than you think. Above all, they will check whether neighbors are affected by your project (even minimally), for example if the silhouette grows by a few centimeters. In the worst case, the neighbor will report you (method of choice if you grill too often twice a month and the neighbor gets bored) and the place will be taken away. Alternatives with greenery and paving have already been mentioned.