The satnav was allowing you to go down that road because it's allowed if you need to access those buildings only. e.g. the cars parked in the disabled bay had to drive through that sign to access the parking bays. I doubt there are cameras on that sign as they would not be able to tell who needs access and who doesn't. But you are responsible for where you drive, not your satnav.
You have no choice other than to go left as directed by the earlier signs. The turn right is specifically prohibited and you can't go straight on as you'd be violating the bus gate.