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Thanks for the answers. Well I called one or two debt collectors and they said most of them only deal in bulk purchases, which we do not have so my next bet is probably to look into getting a solicitor to draw up a letter. I did however drop into one of our debtors this afternoon as I was in the area and the owner seemed quite shocked it had not been paid so I'v given him until tomorrow. I still have some others who I need to persue action with.
In terms of your advice Bednobs, you quite rightly suggest at the end that we never want anything to do with any of these companies again. And I'm not sure they'd be stupid enough to ask us to work for them again. Although that is something we do consider with longer standing customers.