Sorry @avare76 but topup credit cannot be refunded. If you have no use for it you could consider donating it to charity by text.
Note that your topup/airtime credit balance is used to pay for those calls and texts which are not included in goodybags (eg international or premium numbers, using your phone abroad), for when you have run out of minutes, texts or data in your goodybag, or for when you don't have a goodybag and want to run PAYG.
I put £10 credit on account on 25th December. How do I take it out and put back in my bank please.
The other thing you can do with it @avare76 is to buy a goodybag.
However you can’t do this if you have a Recurring Goodybag so you would need to turn that OFF first.
Then buy the bag manually and when you get to the payment page use the “Use Balance” option.
Note: You need to have enough balance to buy the bag you want, so in your case that would be the £5, £7.50 or £10 one, but you can add more credit (minimum £10) before you start the process of you want a bigger one.
If you want to you can re-set Recurring Goodybag as part of the process.