Update.
Someone suggested on the following bill I would see a credit which would even things out, this hasnt happened infact something much worse has happened.
On the new bill I see the credit which was applied after I rang ntl, they credited me 50% of the duplicated bill so 37.99 in February was billed twice and I was credited £18.
This month's bill has £37.99 as normal and an extra £18 for no real reason, it simply lists broadband twice, so I have 37.99 then a 18 credit then 18 readded, I am pulling my hair out right now, will ring them again tommorow but I see myself having another nightmare session with customer services trying to explain the double billing