Australian striker David Seal had a trial with Norwich City, whilst with Belgian side Aalst but was not regarded as being of high enough quality to meet the Canaries' goalscoring requirements. He later joined Bristol City but found a first-team place hard to secure. He was linked with a move to Swansea City but joined Northampton during 1997/98. After a successful first season, David has found it hard to break into the Cobbler's first team in 1998/99. David was linked with a transfer to Millwall who looked at signing him prior to the transfer deadline day in March 1999

Following Northampton's relegation to Division Three, a number of players were released by the Cobblers including David. He returned to Australia to play for Sydney Olympic although The Football Transfers website suggested on 16th May 2000 that David might be returning to England to sign for Chesterfield.

According to reports in the Non League Paper, David returned to Bristol to play for Southern League side Mangotsfield. Seal's 11 goals in the FA cup for Mangotsfield during 2001/02 won him the award of the FA Cup's top scorer, beating the likes of Thierry Henry, Alan Shearer, Jimmy Floyd Hasselbaink etc

At the beginning of May 2006, Mangotsfield announced that they would not be exercising the one year contract extension on Seal's contract freeing him to find another club. In July 2006, he joined Yate Town. He returned to Mangotsfield in December 2006 but left in March 2007 to join minnows Bitton.