I’m a Reservist Flight Ops Assistant (or will be after I graduate this week!) and they’d no issues with that at all. In fact, NATS won an award for their commitment to the Armed Forces last year and have signed up to the Armed Forces Covenant:
https://www.nats.aero/news/nats-reco...ces-community/
You would need to take a career break from the Reserves, certainly while at college as there would be no scope to allow you time out for Annual Continuous Training. Will be different on unit but you would likely need to talk to the unit when you get there about it.