Ok, I have tested this out but something seems to be going wrong:

I created a custom bandit male Redguard and put his health to 1500 to see if he'd be more difficult to kill (I didn't want to increase his strength as I didn't want him to be even more powerful than he already is, I just wanted the fight to last a little longer by adjusting his health).

For some reason, even when I stick his health up to 2000+ the results seem to be the same.

However, my methods work for making creatures more powerful, just not bandits. Which is confusing. Has anyone got any tips on how to mod this? Thanks

you can make a script with
modav health 2000 ;it adds 2000 health to the bandit
(you should get some more scripting tutorials its just the easiest way i think)

Have you a step by step tutorial on hand in regards to this?

My scripting is still in its early stages and I have not come across modav health before, can you help?