Girls.. preferably from uk.. but any update is great!!

Im looking to change my little boys last name. Hes 6. From his biological fathers name to my married name.

His biological fathers on drugs and in and out of prison. Hes not had any contact with him since he was about 6 months. Social services said he was high risk. Im currently going to court to change his last name to my married name. Me and my husband have 2 children together.

Does anyone know what happens at court? Or the chances of the courts giving me the right to change his 2nd name? Any ideas on what i can say in court to boost my case on the name change?

Thankyou.