To 'instruct for beer tokens' in SEP aircraft, whether for NPPL or JAR-FCL PPL(A), you will need a CPL at least.
Remunerated instruction for the NPPL Microlight or SLMG aircraft ratings ONLY with a PPL or NPPL might be possible, suggest you explore the options with the BMAA and BGA.
Have a look in LASORS for the full requirements for FIs.
If you're doing an engineering degree at Impossible College and you're flying with the UAS, I doubt whether you'll have any spare time over the next 3 years - that includes the vacations!