Some ideas to kick around...
I dont think the average chef / waiter knows what we mean by restaurant smell / flavour. I anyone asks, they think they are talking about spices. Chefs seem to think that the clever part is the sauce - something that makes their food palatable to us Brits. The rest is just curry cookery.
I believe that the most important part of producing a restaurant curry happens in the last 5 minutes or so, in particular, the frying of the spices. I have a hunch that some of us are producing the desired result, but for some reason it dosen't 'stick' , it just evaporates away, or possibly something we do destroys it. The smell often seems to be in there when the spices are frying. Maybe some action is needed to 'fix' it.