On Thu, 15 Mar 2018 10:45:10 +0000 (GMT)
"Dave Plowman (News)" wrote:

The rear wiper motor on the old car failed in a cloud of smoke the
other day. The motor had been replaced a few years ago with a NOS
one, so not had that much use.

Did you clean and re-grease the gearbox when you fitted the motor?
I've had wipers completely seize from hardened grease in the gearbox,
wonder if that might have contributed to your motor failure.