Thank you so much for the replies, I don't usually worry so much, but then it's the first time I have had such expensive pets in my care! (Plus Ellie will kill me if something were to happen to them! :p )
Well, since I'm a easy-go-lucky, non-obsessive kind of person, I think I will do like I did with my kids, I think feed on demand/need is probably the way to go, keep up with the wet stuff at regular times and dry food in a separate bowl if they need a snack. That was my first instinct, but I'm glad that others do it that way too!
I'll just have to watch these two, they've cottoned on that kitchen = food, so as soon as someone was standing near the sink/cooker area, they got into their "feed-me-I'm-starving" routine, and as there are quite a few people in the house, it was chaos... So now there's a board on the fridge with their regular feed times and whoever feeds them ticks it, so that the little devils can't keep on getting fed all day long, lol. Thank goodness for apposable thumbs, we can still outsmart them!!!