reducing the loan

Hi . I applied for a full student funding and was granted 6750 pounds however I managed to find a full time job - night shift. Hence I conctacted the saas to reduce my loan. I dont want to cancel it at all as im not sure if i will be able to study full time and work full time. Even the small amount gives me security as I live on my own and cant afford having a small salary.
My question is what amount do u suggest to reduce it to ? I was thinking about 1700. Is there a limitation to working hours imposed by saas if i receive even the small loan like this ?