Hi there,
From the above information I would be quite suprised if you weren't able to get a mortgage. You will find however that the interest rates you will be offered may be slightly high due to the few lenders offering 95% mortgages. You will also need to be carefull with new build properties as lenders are increasingly worried about lending on new build properties due to them being over valued. Are you being offered any incentives by the builder? Is the house price in keeping with the house prices in the local area? I would advise before you put down any deposit then see if you can find a 1-3yr old property similar to the one you want to buy and see how much it's being sold for.
Looking at the lenders who are available you are going to be looking at about 7% for a 95% mortgage without paying silly fees which equates to Interest only payments of £760 a month or Repayments over 30 years of £875. These are only aprox figures but should help you see if the mortgage would be affordable.
Are you using the new build companys broker or your own?
How bad is your previous credit? If you have had any CCJs or defaults but they are over 3 years ago there should still be a lender out there for you.
Hope this helps, any questions hit 'Reply' and let me know!
Dan