Difficult to say conclusively from the PSA image.
A brief description of the two common ways for brake drums to be attached to cars.
The good old fashioned way is for there to be a hub with the wheel studs or threaded wheel bolt holes firmly attached with good old fashioned wheel bearings on to the axle. The brake drum is then passed over the wheel studs - or lined up with the bolt holes - fixed with one or two grub screws, then the roadwheel is bolted on and the brake drum is held firmly in place (being sandwiched between the hub and the roadwheel). Easy to service and no great dramas. See picture:

- Drum brake, 'How A Car Works' - Fair use.
Much more common now there are the wheel bearing-in-drum type drum brakes. The roadwheel bolts / bolt holes are an integral part of the drum and the drum directly takes the load of the the roadwheel as opposed the hub in the above description. The bearing-in-drum type drum brakes basically take the place of the good old fashioned hub, and therefore they have their own version of a hub nut. Normally this would be a large nyloc nut. The issue with this type of brake drum is that you have to disturb the 'hub nut' to get at the brake shoes and/or brake mech.
If you look at the photo below, you can see the how the bearing would sit in the drum, then the drum would be attached to the stub with a nut.

- Integral drum brake 'How A Car Works' - Fair use.
There are normally cautionary tales of the 'must replace the wheel bearing if you disturb it' nature. Some cars this will be essential, some you have to make a judgement call on. On a low mileage car (that I owned) where it wasn't mandatory to replace the wheel bearing, I'd favour not replacing it. You would, however, realistically need to replace a nyloc hub nut with a new one. You could reuse the old one if you really
REALLY had to, but best practice is to repalce it.
To work out what type of brake drum you've got, you could have a ferret around on the PSA parts website to see if you can find a conventional type of rear wheel hub for your ION (as per top photo), or whether there's only pictures showing a hub stub (as per bottom photo).
Edit:
Rather surprisingly, my ageing copy of Docbackup lists the C-Zero, and providing there've been no major changes in the design of the rear brakes since my copy was created, it looks like your brakes are the good old fashioned wheel hub type

- C-Zero rear hub PSA - fair use
Edit II: Cue - the sound of a penny dropping in my brain. Yours is a rare beast.... a modern day rear wheel drive car

Hence it's got the good old fashioned type of rear hub
