The process via the app is OK but the initial connection to load funds was refused. I thought the app was broken or technical fault.
It turned out it was refused by the bank (HBoS) and I had to go through a call with their 2nd tier security as they were suspicious. Had I not been determined to sign up I would have considered giving up given the bank’s apparent concern.
Perhaps have this as a fault finder answer for anyone who has difficulty loading funds - contact your bank.