Maybe if they charged £750 to register a childminder, less people would register.
I found this: \link{http://www.publications.parliament.uk/pa/cm200506/cmstand/d/st051220/am/51220s01.htm\Standing Committee D - Childcare Bill} - Scroll down to Column 299, where it says: "Child minders pay £14 to register with Ofsted and £11 annually thereafter. The registration costs for them are approximately £750, as are the inspection costs."
Hmm, lucky Ofsted isn't a private company... they would be in servious financial difficulty if they were, with a £736 loss on each new registration!
Ofsted can't stop someone from registering just becasue there are other childminders already in the locality. Thus in some areas it's possible to have a lot of childminders, and not enough children to be cared for... and in other areas parents screaming out for childminders.
Maybe EYDCP need to encourage people thinking of becoming a childminder to do more market research, and more competitor analysis, before deciding to become registered.
Sorry, can't really help with how to fill vacancies. Is there anyway you can find out how many parents are actually looking for childcare in your area - CIS may keep stats of enquiries, and thus may know postcode regions of where most enquires come from, so you can then target those areas. Not sure CIS would share the info, but hey, if you don't ask, you don't get.