I think Moorcroft are indeed a legit debt recovery agency who do work on behalf of Lloyds, I think it was them who I ran up against over a parking ticket from Herefordshire Council as well.
However, that doesn't mean it's correct.
What they definitely are though is nasty bast&rds...
They initially handle it in the office, then hand it over to their bailiffs who are basically thugs and have NO REGARD for the law, so try to nip it in the bud before it gets that far.
Write to them and send it recorded delivery, requesting copies of all information they hold relating to this debt and ask for them to confirm who retained their services.
If it says Lloyds on the letter, then phone LLoyds NOW on 0845 3 000 000 [keep pressing * to bypass the options] and then give them all the information you have and ask them if it's correct and if not, can they put you through to the department which deals with arrears & debt.
It may have been from the court, although I don't think they're actually court bailiffs so despite what they WILL tell you they CANNOT legally enter your property.
If they do indeed have a court order to recover the debt you need to find out which court issued it and request a form which needs completing and returning which will freeze the order.
Whether it's correct or not, I hate to tell you this but this could become a real pain in the arse and you need to take it seriously and sort it out IMMEDIATELY or they could really spoil Christmas.
If the letter is from Moorcroft - Moorcroft Debt Recovery - then PLEASE don't put off doing something about it. I can tell you from experience that it's the most horrid experience I've ever been through, if you have a family you need to stop this before they do set the bailiffs on you because as I say, once it gets to them it's VERY difficult to stop them, they are effectively independent, set their own charges and will only stop when given a very specific command, they don't care if what they're doing is illegal. If they pass it to their bailiffs they will be trying to lift at least twice the claimed debt amount off you...
Phone LLoyds NOW!