What's the difference between FSH and FMDSH?

Both mean the car has a full service history, but they differ in where the work was done. FSH (Full Service History) just means every scheduled service happened and was recorded - it could have been done at an independent garage, a chain, or a main dealer. FMDSH (Full Main Dealer Service History) means every one of those services was carried out specifically at a manufacturer's main dealer for that make.

What it means for a buyer: FMDSH is generally seen as slightly more desirable, since main dealer work tends to use manufacturer-approved parts and procedures, and it can matter more on newer or higher-value cars. For an everyday used car, a genuine FSH from a reputable independent garage is often just as reassuring in practice - what matters most is that the work was actually done and recorded, not necessarily who did it.