Can anyone recommend a good, large, black backpack please?

[hogu]

I have a toddler so don't want a changing bag but need it to be quite big to shove a million things we take out with us!

I don't like the nylon bags so preferably leather.

Budget up to £300

Someone please help me!

This Whistles bag? I use mine for work, but a friend uses hers as a nappy bag. It's spacious and durable.