Changing stereo, new one won't fit- Daihatsu Sirion M301


First time posting on this forum, first time changing a car's radio and it's given me quite a headache recently.
I figured it'd just be a case of unplugging the old one (which I managed to do), connect everything, and that'd be the end of it... But I've had to buy new wire adapters (it plugs in, turns on and plays at least) also had to get a fascia plate that supports standard DIN stereos and a single DIN pocket to fill the space the new stereo unit leaves, the stereo I've got is a Maxtek vision with bluetooth display from ALDI.

The fasica:

The problem I'm having is all of this doesn't seem to fit or secure into the dashboard properly, I thought this radio was a single DIN and I could just stick a pocket into the empty space, but the stereo and pocket don't seem to line up with the fascia plate or secure into the dash. The holes in the dash where you'd assume it screws in don't match up with the radio, even with the included harness, I don't see any way to secure it in place. Went to Halfords to see if they could help me but their sound system guy spent a good hour trying to sort it out with no success, and told me to contact the fascia plate manufacturer, which I did, they weren't much help either.