FDM Group interview questions

Got a call after leaving them my CV at a graduate fair. You get assigned a recruiter who takes charge of communication with you, conducting the initial phone interview he/she sees if you are a suitable candidate. I'm guessing due to commission for these recruiters it is in their interest for FDM to hire you. They explain their assessment process giving you tips, answering any questions you have in detail. In the assessment centre there is standard aptitude testing, pretty basic, also "quick-fire" interview rounds. Got offer the next afternoon after attending the centre. It is a successful and a fast growing company with an impressive list of clients, with good chances of being employed by one of those clients in the end. However what got me cautious is the feeling as if they were 'selling' something this whole recruitment process, and also the number of candidates attending the assessment event, I got a chance to ask the receptionist and she told me assessment centre takes places 3 times a week. (!!) The contract I received post offer is quite sinister. They give you a few weeks worth of programming training consisting of different modules. These modules total some crazy sum of money (but is capped at £20k) which you will have to give back to FDM if you try to leave before the contract period is over. This sum is waived only upon the end of the 2 year period, and some strangely worded conditions. The initial period of up to 3 months is unpaid, it is when FDM keeps you at their disposal until a suitable client is found, 2 year contract period only starting after you are placed with a client. What FDM does is basically abuse the current over-supply of quality university educated labour, who straight out of university are ready to sign anything, enslaving them with this contract. There is currently a great shortage of IT related workforce in UK, they retrain you and in turn earn nice margins on selling you to their clients.