Changing bag/travel bag

[Mamabear141]

I'm looking to get a new changing bag, for big family days out, as the one I have works for normals days but I need more space on family days out.
I have one little boy he is bottle feed and he feeds every two hours, if we are going far I usually take four bottles out with me, he'll usually get through three and the other is just an incase bottle.
I need one that can fit all his bottles, change of clothes/nappy stuff, some snacks for him and a few mummy's bits for me. I have tired the Pacapod Richmond and I hated it! So I then bought a backpack style from Amazon really cheap and I love it but need a bigger version. Any suggestions?
Only looking for backpack style

I use a LV neverfull for my twins (GM size) and it fits everything in.

Neverfulls aren't backpack style...
Bababing does a backpack and I really like the way they have clearly labelled sections for different things.

I have absolutely no experience with changing bags (expecting my first - so my suggestion might not be very helpful), but I've bought a large Longchamp travel bag that can be expanded if need be.

uk.longchamp.com/products/le-pliage/travel-bag/l1911089645

I found it in the Longchamp outlet in Bicester Village for a bit less, which was nice.

I'm thinking the normal (so zipped) size will be fine for most days - the bag is light in itself, and I'd probably just keep it in the pram, and if going out for longer or travelling, we can expand it.

I can see how a backpack would be easier to carry around though.