I've not ever heard this term used in any real life way - [managing debt] possibly, [debt managing] afraid not.
Google gives 0 searches for the UK and 170 globally per month for this, which backs the above up ie it's not just me (out of the 60 million people in the UK - no-one is doing a single search for this, which might explain why it was free to register).
I think you'll be lucky to sell this at any sort of a profit, so IMO the reg fee was wasted unless you want to develop it as a site, in which case having [debt] in the domain might help.