Has anyone found a compact backpack that looks like it'll suit the air 2?  

Got a couple I use for my camera's, but I want a dedicated pack.  The ideal scenario is one that'll fit the Mini/controller + Air 2/controller. With not much space to spare.

Other option is to buy case foam, and just quick swap into an existing pack.  Anyone know a good source of case foam at a good price in the uk?  Expensive on amazon.

Take a look for Lowepro Photo Traveler 150 Backpack.
It's quite compact backpack and I used this for MA1 and Osmo Pocket at the same time.
The controller of MA1, I moded with 4 Hawks so it became really bulky.
That's why I found this bag, the original DJI crossbag didn't work for this controller.
I think you can put Mini and MA 2 at the same time. (Not sure how many batteries you have.)
I already sold MA1 and waiting for MA2.
I'm sure this will fit to my need.

Pilot.Isaac Posted at 5-13 22:19
Take a look for Lowepro Photo Traveler 150 Backpack.
It's quite compack backpack and I used this for MA1 and Osmo Pocket at the same time.
The controller of MA1, I moded with 4 Hawks so it became really bulky.

Great, thanks for this, I’ll take a look.

So many of the bags I've seen are  just too big.