Adoption requires a great deal more than contacting a Register Office, Dot!
A court order is needed. That can only be granted after your local council's social services department has produced reports relating to everyone involved in the process, including both natural parents, your boyfriend and your daughter. (A police check on your boyfriend will be needed).
Further your daughter's natural father has to give his permission, as he will lose parental responsibility. The only exceptions are if he can't be traced, if he's incapable of giving consent or if delaying an adoption order would put your daughter's welfare at risk.
The whole process is extremely lengthy. Your boyfriend is required to notify social services of his intent to apply for a court order at least three months before he does so. In practice it would be best to allow longer, since checks by social services and the police can take a long time to complete. Then the court process is likely to take several months further. You and your boyfriend should prepare yourself for a year of hassle and doubt.
http://www.direct.gov...Fostering/DG_10021340
Chris