The visitors began badly when fly-half Steve Meyer missed a straightforward penalty just two minutes after kick-off, while Meyer was sin-binned in the 16th minute for not retreating 10m from a quick tap penalty.
Gloucester carried that momentum into the second half and after Ben White was sin-binned for slowing down the ball, they moved the ball right after a quick-tap penalty for Simpson-Daniel to score and Robinson converted from the touchline.