Are you in an IVA? If so you will fail any credit checks. Better to be upfront with agencies and see if they will work around with increased deposit, more advance rent or a guarantor. Otherwise try private landlords who don't use an agency, who do not usually credit check. A reference from the present landlord will also help.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014 http://foggy.blogs.iva.co.uk
You may need to provide 6 months rent up front - to do this is impossible when in an iva unless you have family member willing to pay it out for you as a gift.
Best to find a private landlord and be upfront with them
Sharing from experiences of dealing with debt
There is a solution for everyone .... Just need to stay positive !