if you show up as having medical issues, they pursue every avenue. In my case, when I had a pacemaker fitted in 2004, the NHS informed the DVLAI think that is only in certain cases, i.e. when the D4 answers raise some doubts. It has never happened to me after 3 D4 Medicals.
I am not sure they know who my GP is - do they ask on the D4?
Geoff