Southwell is bound for Stade Francais, where he will join up with fellow Scotland man Simon Taylor, after several successful years with Edinburgh.

Meanwhile New Zealand-born Mustchin is leaving the capital for Japan after the bonus of earning Scotland caps during his stint with the club.

It is unlikely that Mustchin will ever play again at Murrayfield and the abrasive forward signed off with an energetic performance before being replaced by Alan MacDonald.

In contrast, Southwell, who entered the fray as a replacement for stand-off Phil Godman, will hope he returns to Scottish rugby’s HQ as early as the November Test series under the new national coach.

Failing that, the cultured full-back will seek a return to the Scotland squad for the RBS 6 Nations in 2010 - but much will depend on the amount of game time he can secure at star-studded Stade.

It was Southwell’s Scotland team-mate Chris Paterson, whose return to Edinburgh from Gloucester may well have accelerated his exit, who scored the majority of the points for Edinburgh against the Dragons.

Paterson contributed 28 points as Edinburgh ran out 43-3 winners to move up to third in the table, John Houston, Ben Cairns and Ben Meyer also crossing for tries as the Welsh outfit were thrashed.

Edinburgh now travel to Cardiff next week to finish their league programme hoping to secure an impressive second-placed finish.