According to the Teignmouth weather station the Jun/Jul/Aug total is currently around 440mm. I know it's been wet, but I find it hard to believe that Teignmouth has been wetter than Haytor, though Dawlish's total is around 360mm.

Teignmouth weather station http://www.teignmouthweather.co.uk/past_3months.html
Dawlish weather station: to 17th Aug 336mm + 14mm today
June http://www.dawlishweather.co.uk/holcombe_jun_12_sum.htm
July http://www.dawlishweather.co.uk/holcombe_jul_12_sum.htm
August to 17th http://www.dawlishweather.co.uk/holcombe_aug_12_sum.htm
Today http://www.dawlishweather.co.uk/currentweather.htm