Again, it depends what you class as family use. For me at least the Focus hatch is also too small, the estate is useable though. By the time you've got the tent, 4 sleeping bags & mats, cooking equipment, and a couple of body boards in there, it doesn't leave much space for stuff like clothes
Inb4 "yeah but nobody goes camping any more"
Not me, but the rest of the family. I'm guessing you don't have kids
The MG4 would be OK if it had roof bars on for a box. Like I said, for day to day use it's absolutely fine. If you're happy renting a bigger car when needed, it's absolutely fine. if you have another bigger car/van to use, it's absolutely fine. If it's your only car and your family is vaguely active then (imo) you're going to struggle.