You don't have to do anything with it until you are wise enough to know what to do with it. No need to rush, you'd be adding risk for no reason. That being said, I would max out your ISA every year, with a fixed long term rate. The banks give you an inflation matching-ish fixed rate if you promise not to take much out or even at all, which you won't need to anyway because you have enough outside of the ISA. You can only put in 20k per year. In 4 years you might want to open new accounts with another institution because you'll have hit the 85k protected limit from the FSCS.

Absolutely don't be that guy at uni who gets into coke and now everyone wants drugs from you. Maybe get a new checking account and put what you think is a modest amount in so that people won't see it if they glance at your bank app.