I thought at least on the Thomsonfly scheme Thomsonfly are involved in the selection of the student. Therefore students accepted on this scheme will have already passed Thomsonfly selection and as long as they do well on the course and Thomsonfly have vacancies when they finish they will be first in the queue.
I said it before (and got shot down in flames!) but the Thomsonfly scheme is not really any different from CTC and yet everybody accepts CTC as a valid route these days. In both CTC and Thomsonfly the student has to provide ALL the funding (help is provided for sourcing) but, even at CTC, if times go bad and there in no job at the end (no guarantees!) the student still has to pay off the loan.