I know this might be a bit of a long shot, given the state of this moth, as brought in by the cat, but can anyone ID this hawkmoth?
I thought it might be a Convolvulus hawkmoth, based on the hint of stripes on the body, some black and white markings on the fringes of the wing, and a wiggly bit on the point of the wing… but it's hard to be sure because of the state it's in. And it looked on the small side, maybe.
I would say your hunch is right - Convolvulus Hawk-moth. They are very strong flyers and long lived as adults, any remaining at this time of year often appear battered and de-scaled as this example is. Remarkably they can still fly in this condition but as their nectar resources peter out they are left a bit low on fuel.