The only thing I can suggest is calling 150 and ask them to check your account to make sure both No's are in the same family as with an unlimited contract you can gift up to 100gb between your sims
@PaulC59 I remember talking to ee customer services last year and he said he could put some of my 150 gig data onto my other phone but it would cost £7 a month so i said no
You need to call EE and ask them to put both your Sims in the same billing account. The No's are at the top of the screen when you open the app with a drop down arrow so you can switch accounts