The pair added 188 for the second wicket off 154 balls and with Rob Turner increasing the tempo even further with 45 off 23 balls the visitors reached their highest total in the competition, 322 for 4, despite the reduction in overs.
Lathwell's 121 included 15 fours and one six and Ecclestone's unbeaten 112 won him the Gold Award.
Gloucestershire had Andrew Symonds, now apparently committed to England and watched by the England selector, David Graveney, to thank for their five-wicket win against Sussex at Bristol. He faced 59 balls for his 67, hitting eight fours and two sixes.
Craig White showed he has recovered from the severe strain that forced him out of England's tour last winter with an unbeaten 57 and two wickets in Yorkshire's 69-run win against Nottinghamshire at Headingley. Yorkshire's new captain, David Byas, scored 81, and Alex Wharf took 4 for 29.Reuse content