Applying for Canadian Permanent Residency

Please pardon me if I am asking a question that has been asked before. Here is a summary of my situation:

I am currently residing in the UK (on work permit) and had put in my application for permanent residency in Canada under the Federal Work Category. I put in the application two years ago and I have now been invited by the Canadian High Commission in London to submit a fresh application with the supporting documents. My situation has really changed within the two years. I now have a daughter who will definitely be migrating with me. I am not married to her father though and do not intend to; we live in the same house but there is currently no relationship between us hence I cannot say we are in a common-law relationship. We just decide to live together till I am able to sort out a better accommodation for my daughter and myself. Do I need to get a consent letter from her dad stating that I can take her daughter with me to Canada or do I have to get a letter from a court for this.

Presently, her dad is very happy for me to take her along but how do i prove that to the Canadian High Commission. Please is there someone out there who knows what I should do or who have been in similar situation. Any advice is highly welcome.

Rgards