"Breaking any of these moving parts could have disastrous consequences"
My experience exactly. The Pay Existing Payee page does not have the same Look and Feel as the rest of the site, it looks like something a teenage script kiddie knocked up in half an hour, and it doesn't work with Firefox on XP, hanging at the "Continue" stage. I have reported this to Santander, and they just shrug and say "Use Chrome". Not a viable solution to have to change browsers just to use one part of a site which, otherwise, gives me no problems.
Biting the hand that feeds IT
