Initial read...too much May and not enough Slaughter
Skimming through the report the only real surprise must be that they got through it at all.
TSB/Sabis appears to have known prior to the migration that their testing was woefully inadequate and that they didn't have the necessary capacity in a number of key areas and would likely fail to the extent observed if they reached their predicted load. Rather than addressing the issues, they reduced the size of the tests...by around 50% when actual load turned out to be ~300% in the case of the mobile platform but there appears to have been no area where they had adequate capacity at day one irrespective of application issues.
And this wasn't just known by technical staff or project management teams - it went to the CIO levels of TSB/Sabis and possibly beyond (still reading...)
I've been through some shoddy project go-lives where we knew there were major issues and areas that we would likely have to fire fight for weeks or months, but this seems particularly poor.
And I assume this is the carefully polished, gold plated turd that TSB were happy to release to the public rather than the in-depth, detailed report that will help the organisation grow and avoid a repeat of this issue.
I look forward to the FCA/PRA investigations for an even more damning insight into what happened.