Historical clue formulations

• Regatta site since 1839 — 2018-07-08
• ___-on-Thames (regatta site) — 2016-08-20
• Regatta setting — 2009-01-16
• "Crimes of the Heart" playwright Beth — 2007-12-09
• Singer Don of the Eagles — 2004-07-12
• Regatta site — 1994-09-20