The T1 Acquisition Protocol version meanings resource provides the link between the confound integers in the Acquisition Protocol Version field and the Study Description header field in the T1 DICOM.

This resource can be downloaded or viewed using the link: T1AcquisitionProtocols.txt

If you have wget available (typically on linux systems), then you can also obtain a copy using the command

 wget  -nd  biobank.ctsu.ox.ac.uk/ukb/ukb/docs/T1AcquisitionProtocols.txt