Facetime - swapped sim not numbers

[Colvers]

Hi, i recently got a new sim and kept my old number however facetime uses the new sim card phone number to call out instead of my old number.  It doesnt give me an option in Settings>Facetime to swap to my old number even though its fine for everything else.  Can anyone help please? 

[Oxonian]

@Colvers 

This might help :-

Add or remove your phone number in Messages or FaceTime – Apple Support (UK)

https://support.apple.com/en-gb/108758

[MI5]

@Colvers 

Settings >Phone >My number.

Edit, save and reboot.

If number won't save, reset your network settings.