Caught up with debtor tenant !

I have recently carried out a trace on a tenant who left leaving nearly £3000 of arrears in October 2005. Although I did manage to collect some money out of him he still owes me just over £2500.

I therefore handed over debt recovery over to a firm called 'Corporate Assignments" in Dec 2006 but despite repeatedly contacting them, they provided me with no updates until when I called them yet again recently they mentioned the debtor was placed on a 'Debtwatch scheme' which meant they had failed to trace his whereabouts, current employment status. Therefore annoyed that 3 years has been wasted especially when I managed to trace him myself.

From the recent trace, I have his current address and confirmed he owns that house with his partner from a Land Registry Search (he has owned it since Oct 2006). I have however no employment details, although tracing firm mentioned a neighbour thinks he's self-employed - not sure how credible this is though as he worked for railway firm until at least late 2008.

I am therefore looking for pointers on how to proceed, i.e.

1) By what other means could I get useful information on the debtor - e.g. employment status, bankruptcy, IVA to establish whether worthwhile pursuing the debt ?
2) I still have the original CCJ from the court with the £3000 judgement going back to Oct 2005. Do I need to reapply to courts for another claim or can I just use existing claim to apply to the courts for attachment of earnings, charging order on his house, etc?
3) Regarding the current firm I have been using (Corporate Assigments), I actually assigned the debt to them in Dec 2006, how do I go about cancelling any arrangement I have with them and using another firm, etc.

Thanks in advance. Sorry about the long-winded note !