I've had two motorcycles stolen in the UK. The police gave me a crime reference number and sent out a victim support letter; that was the sum total of their apparent effort.
Well, presumably they'll also have placed the VIN (or equivalent) on their watchlist. But aside from that – what do you expect to happen in the case of a crime like that?
Come and look for evidence? Finger or shoe prints? Check if there are CCTV cameras that might have been covering the area? Interview neighbours and see if they saw anything? Confirm if you did actually have these motorcycles and that this isn't an insurance scam? Advise you on how to better secure them in the future?
Something tells me that if it were the chief of Police's motorcycle stolen, the bobbies might be a bit more energetic in recovering it. Probably what the GP expects is some subset of what they would do for the chief.