We had a lovely stay with our toddler in Scarborough. The views are absolutely better in real life!! The apartment has everything you need and feels incredibly spacious. It's very convenient being close to supermarket and cafes (though it would be difficult to get around and explore Perth without a car!).
Unfortunately we were there during very hot weather (40 degree days) and the bedrooms got very hot without aircon, leading to sleepless nights for all of us! Also, Scarborough beach is not for the faint hearted - not ideal for toddlers....