Oxfordshire County Council housing-led forecasts (released August 2018) for small areas.
The downloadable excel workbook gives rounded data for districts and Oxfordshire by 5 year age bands from 2016 to 2026.
The assumptions used in the forecasts are provided in the front sheet of the workbook.
The areas used for these small area forecasts are Middle Layer Super Output Areas, a statisical geography. There are 86 MSOAs in Oxfordshire with an average population of 7,600 and a map showing boundaries is available here.