Remove redundant code
Remove redundant code

Addresses code review comments

annapowellsmith/openpresc,ebmdatalab/openprescribing,ebmdatalab/openprescribing,annapowellsmith/openpresc,ebmdatalab/openprescribing,ebmdatalab/openprescribing,annapowellsmith/openpresc,annapowellsmith/openpresc