I have changed my mobile number and my verification code got sent to my old number

[spaffy]

Detail above 

[GD1]

@spaffy  Did you update the mobile number within your email account before changing the number on your phone?

[Mark39]

@spaffy use your Recovery Code (you did keep a separate note of it as Sky recommended?) to turn off 2 step login. You can then set it up again with the new mobile number.

[spaffy]

I don't have a recovery code, wouldn't know where to find, I set up my email over a decade ago 

[spaffy]

Nope, tried ringing sky very unhelpful 

[Mark39]

@spaffy if you set up 2 step login, a Recovery Code was displayed on screen, and sent by email to you.

2 step login was offered within the last 12 months or so, so nothing to do with when you set up your email account. 

What happens when you try to sign in here: https://www.sky.com/signin/email Error message?