I believe it was run in the same configuration as the Norsk Aircraft was in, following it's pump (drive) failure - the oil cooler bypassed (so no cooling) and the good pump driving oil predominently through the windmilling 'failed' pump, thereby providing some, but very little, pressure - close to 5 psi. I think it was run for around 3 hours, as John confirms.
The outcome was extremely favourable, from a technical perspective, insofar as the mechanical integrity of the dynamic componants was extremely sound i.e. there was no damage. That's not to say that there would not have been a whole bunch of very unpleasant cockpit indications, had the MGB been in flight, with secondary failures of the AC Generators likely and probably smoke and smell. It got very, very hot!