Well, I'd better get the embarrassing bit over first... She's sorry but now remembers that it was on the outgoing flight rather than the return. This means that she saw it at PMI while boarding her Swiftair (?) ATR72 for the 1040 hrs. Air Europa flight to Alicante on the 29th. of January.
She seemed fairly convinced by the various suggestions of a Dash 7 but remains to be fully so because of its lack of blades!