Ever read a lessons learned document?
They've thrown a migration and upgrade together (never a good idea) and also considering timelines, they no doubt have dumped a load of new GDPR code to support next months change into the mix.
More than likely run by one of TSB's first attempts at a psuedo agile project.
At some point over the weekend a decision was made to go live and not restore to the backups and now fixing forward a steaming pile of shite is the only option hence the site being up and down like a (insert similie here).
Biting the hand that feeds IT
