Our local petsitter will come in daily, moving in can be a lot more expensive. Definitely worth it. The other option is to explain to your kindly neighbour that puss really needs two meals, not one feast, and offer her a few quid for inconvenience. Your cat would far rather be in his own home, even if the food is less frequent - he's a very old man. He might fret in a cattery with no familiar smells and sleeping places, and be confused. I'm always happier leaving my cats at home and arranging for people to come in.