He made a try-scoring debut at Murrayfield as he crossed the line against Australia in the opening match of the 2004 Autumn tests which was the first of his eight international tries.
Southwell was restored to the Scotland line-up for the 2005 Autumn test against New Zealand and rewarded Frank Hadden with a fine display against the All Blacks.
He still maintains the ambition to play first-class cricket, once his rugby career is over, in the hope that he will be able to fulfil his dream of becoming a double international.
This support was to the dismay of Frank Hadden who had previously voiced his concern over Southwell's cricketing ambitions ahead of the rugby internationals against Barbarians and the two-match Test tour of South Africa in 2006.
Hadden had wanted the Scottish Rugby Squad to rest ahead of the showpiece games and was concerned that Southwell, who took three wickets for Heriot's and hit the winning runs against Edinburgh Accies, decided to play in the Masterton Trophy instead.