Earlier quoted context omitted.
company doctor?
In EU companies have to appoint a medical expert that checks worker's health (for free) upon joining the company, and routinely (1-2 times a year, depends on country I guess). Edit: Could be something that only companies whose workers have to do physical labour ("blue collar" jerbs) If you call in sick for more than three days you usually go through your own doctor, so that you get a certification that you're taking…
In theory you should get a sick note after 3 days, because the government pays SSP (statutory sick pay) if you're ill, but in practice most companies pay you at your normal salary rate (if you're permanent, not per hour) and don't bother asking for sick note as the SSP is little more than minimum wage. Of course, this is in tech, I know that there are a lot of crappier jobs where employers trust their staff less, and I suspect in those industries the sick note is very much required.