Change Default Date

Hi all,

I have checked my checkered credit file and have found I have around 4 defaults applied 9-13 months after I entered a DMP. One of these accounts was an overdraft which I understand is treated slightly differently, as there are no repayment terms but still - do I stand a chance of getting these brought to when I started or atleast to the 6 month point at the most after it started?

Thanks in advance