A temporary speed indicator device (SID) has been installed on Stratford Road today. It's situated between Mill Lane and the school.
Traffic travelling towards Salisbury will pass the indicator whilst still in an area that is subject to a 20 mph speed limit when the the new warning lights are flashing during school dropoff and pickup times, see earlier news story: https://www.stratfordsubcastle.org.uk/post/approaching-stratford-school-20-mph-when-lights-are-flashing
It will be interesting to see what the display reads during those times...