Looks in bloody good nick to be fair. I'd lower it, get some alloys on there (go for OEM, maybe f1's, or something similar) and not a lot else tbh. Just keep it looking tidy.
OP is 17.
Just bolting lowzzz and rims will take their premium and send it skywards.
Welcome aboard Matty, here's some thinking for you.
Your car cost 800 quid
Would you then spend another 4/500 on wheels and suspension?
Then, probably, a big chunk more on insurance?
Being a student, there must be better things, more deserved of your money (THere sure was when I was still in education!)
You might want a "nicer" motor, but just see how you get along first. If you bolted on shiny new rims then immedieatly kerbed them, how happy would you be about that.
Plenty of time for nicer motors later, the kind you can buy that already have bigger engines, alloys, etc. JUst stay safe, dont crash, build up that no claims and enjoy it for what it is.
WOrk with the steels you've got on now, spray them in Gloss black maybe?