You should ask the seller for all the information you need about the bike, because a) they should know more than we do and b) if they can't give it to you readily then there is more risk that it is stolen. These things do happen!
Don't tell the seller this, but the name is usually written on the frame. If they can't manage that much then consider walking ...
It looks like a 2017 Giant Contend SL2 Disc: https://www.giant-bicycles.com/gb/contend-sl-2-disc-2017.
The picture is quite grainy so it's hard to be 100% sure. Check if it has the Giant Conduct disc brake system to be sure.
Here's the image in the linked product page for the 2017 Giant Contend SL2 Disc:
FYI I use simple prescription glasses or sunglasses, where the frame is attached to the top of each lens, but not down the sides of the lens nor underneath -- so there isn't a frame at the side of the lens, blocking vision.
Also the arm (between the frame and the ear) isn't thick.
The lenses are long-distance only, not progressive.
Drop bar one works well for me.
It provides good visibility and I feel is safer in a crash vs. one that is mounted to your helmet. Note, I have crashed with one on the handlebar after catching a longitudinal crack in the road and did not have issues, but I worry that a helmet/glass mounted mirror could pose a safety hazard in the case of a crash.
Looks like a nice bike - not very old because disk brakes have only been on road bikes in the last ~5 years.
The top tube profile suggests an aluminium frame not carbon fibre, and the thickness of the fork tines/legs suggest they are carbon fibre.
Both tyres are a bit low on air so pump them up before you test-ride it. And you should absolutely test ride ...
Check if they have eyelets for a rack. It is the single most useful thing that can discriminate between them, to understand if they are a good fit to be a commuting bike.
I would then say Scott sub speed 20. With the saved money you can buy a very good lock and some tyres with a grippy thread, but not too wide (if yours has mudguards).