The tablet is great, at being a tablet.
But as a final year university student myself i can say without a doubt that you will need a regular laptop, because alot of what you do, uses apps and services that are only available for Windows.
Even writing reports and doing research, at university level this is a tremendous amount of work, not one that can be done on a tablet. Pretty much every course will require you to download certain apps and tools that are only available for Windows. So you will 100% need to buy a computer unless she wants to try her luck at renting the universities laptops or travelling to the university library in order to do any work.
The tablet is great if your just doing some light work, maybe doing some quick editing of a document or some light browsing, but accessing the university services, their own intranet, the softwares you will need, they are usually only available or optimized for windows, with support for Linux.
Not to mention, formatting a document in Word on a mobile device such as a tablet isn't the same as on the desktop version, and you will find that being able to format a proper technical report can be 10% of marks in a technical report or essay.
And on top of this, with the amount of workload and hours you will be putting onto the tablet if she were to try her luck at using it for university, the battery just wouldn't last and eventually you'd need a new battery or new tablet after only a year or 2.
My suggestion, with the price of the S7+, is to ditch the s-pen and buy a Galaxy tab S5e, and a basic laptop which the rest of your budget, which i assume would put your laptop price in the sub £400 category which is good enough for university work (unless her course is any form of engineering or computing, then ud need a gaming style laptop to handle the software, trust me i know, my course is engineering)
TL;DR
1) University apps/ Course specific softwares aren't available on android, only Windows
2) University workload is massive and a tablet battery won't even last 2 years before needing replacing, assignments takes hundreds of hours to do, and heavy use of the tablet drains the battery fast needing multiple charges in a day and massively shortening its life.
3) Formatting documents in Word on android doesn't show up properly on desktop, and citing references can't be done properly on the mobile version of word either, plus you can't add the required Word add-ons you may need for writing reports or essays.
4) Put the budget towards a cheaper tablet and a laptop. (Galaxy tab s5e is my recommendation, as i have one.)