Understanding Society User Support

Hello,

I would like to use the variable month of birth.
According to the online documentation:
- in the understanding society databaseit should be available in indresp wave 1 and 2 only (the variable is called scdobm); is this question made available in some other datasets?
- in the BHPS database it should be available in all inderesp waves (the variable is called dobm)

However I dont find the variable in the databases I have just downloaded.
I have tried to download the two the following dta
1) BHPS series only: https://beta.ukdataservice.ac.uk/datacatalogue/studies/study?id=5151
2) The harmonised version of BHPS and UKHLSE: https://beta.ukdataservice.ac.uk/datacatalogue/studies/study?id=6614

Any idea what can be wrong?
Thanks,
Maddalena