To undo the bolt attaching the brake mechanism to the fork, you need a Torx 25 star-shaped bit.
I had one in my toolbox, but they are readily available at DIY shops - just google ‘torx 25 bit’
There are two bolts on the brake mech, but it is only the bottom bolt which screws into the shoulder/boss on the fork, I didn’t touch the top bolt.
Removing the bolt enables you to lift the brake mech off the fork on one side, and the wheel can then be removed without deflating it - I have fitted wider schwalbe marathon 700/35mm tyres, but needed the mudguards moving slightly so they didn’t touch.
The brake mech bolts back on easily, and seems to need no adjustment. I keep a torx bit and screwdriver bit holder in my bike bag now in case of any more punctures.
I've also fitted ‘Slime’ innertubes to reduce the chance of a puncture.