Hi bro, not yet solve it.. I had to trouble my family to find out for me as I left for holidays now.. I also signed up, chose a number. Once I know will update here.
If you choose a number when you sign up starhub fibre, you cant port your M1 number to starhub as one fibre can only have one number.
I also had ask M1 shop at NEX before if i can port another number to M1 fibre with existing having a number tag to it. They say i need to port out the existing number under fibre before i can port in the number from another telco.
I had ask M1 because Starhub tell me to port out my number to another telco if i want to retain my number for homehub when i sign up the 5Gbps plan because they say cannot transfer within same telco.
Actually whether can transfer within telco or not depend much on who you speak to. Same goes to applying for $29.55 5Gbps fibre.