On Sat, 11 Jul 2015 10:10:40 -0400, Pat wrote:

Some supplies will not regulate voltage without a load. Try measuring
it again with a small load (eg, a 1K resistor) across the supply.

Good point! Still doesn't check-out, though.
Rated current at 12V is 500mA, so a 50 Ohm resistor would be more
appropriate. Managed to find a 47R power resistor and connected across
supply. Now reading 14.45V, so deffo not right...