Deposit Protection?

Tenancy Deposits

we have a student who signed his original joint contract in 2006 paying £250 deposit to the landlord (4 tenants £1000 in total). Two of the original four moved out, and in 2009 2 of the originl 2007 tenants and two new tenants signed a new contract. our student has not received his deposit back from the landlord during this period. he vacated in june 2010 owing rent. these rent arrears have now been paid in full.

1. was the landlord legally required to register the deposit in 2009 with one of the TDP schemes?

2. Do the rent arrears have any bearing on an application that student may make to the court regarding failure to protect.

thanks

Bev