I collected some more information from SpeakEV and some Tesla owner’s forums:
GPS: 56.386000, -3.479200
Power: 120 kW (all UK sites still 120 kW AFAIK)
SpeakEV thread includes links to council planning documents confirming location and number of stalls. Six Tesla crates already delivered to site, presumably the charging cabinets for the 12 stalls.
Site preparation spotted 27-Jan-19 (area coned off).
GPS coordinates should plot at southern end of Broxden park and ride car park.