doesn't like losing her commission
why is your sis using an agency anyway ? she could have done it herself, as some have already done on here. maybe a higher risk of refusal if you did it yourself, as these people have a better understanding of what you need to do to get a visa, but with the info already on here about applying for a student visa, i'm sure she would have had the same chance of getting a student visa without needing to use a agency.
what your sister going to study ? , you know things will be more difficult from march if shes doing a NVQ, next month

, half the time must be class based.