Stanley was in the C Sqr Fitters' half-track when it was ambushed between the village of Presles and the climb up to the Perrier ridge. The half-track took a direct hit from an H.E. shell. The incident is described in the 23H Story Page 96+ and a full account is here.
Stanley's grave gives his date of death as 6 Aug. That is incorrect. The C Sqr ROH in Bridlington Priory shows the correct date.