Late in Protecting Deposit.

Tenancy Deposits

My Tenent is constantly late in paying his rent so when the 1 year AST was up in Jan 2010 and he refused to leave i had to issue a S21 which is due on march 29th.
He now has contacted the Tenants Deposit Advise Service who have written to me as i did not protect the deposit at the time, but did do Jan 14 of this year, stating that i now have to pay 3times the deposit otherwise court proceedings will start. Looking at the help forums i read that if the deposit is secured before they start a summons i do not have to pay. Is this still the case? If so, what is the next step. I do not want to get into a long court case, (you're just swapping giving money to one person to another) i just want to get the house back and, hopefully, in good condition and put this behind me.

Thanks

IT