FTR this switch has 30 devices plugged into it and none of them are active. Affected users devices have all fallen back to WiFi so most are unaware of the fault.
Time to get the networks team involved.
@renbymon Just the tail sticking out of it
@noodlydragon Oh gosh yeah
"Who wired these cabinets?!"
@renbymon Be careful not to get eaten by the mimic server rack :D
As suspected the switch had fallen over. Local restart (pulling and reseating the power cables) fixed the fault!
This has reminded me that I should put an Ethernet cable tester into my work tool bag.