A good full service checking all ~50 items on the service list should take between 2.5h and 3h on a average car. Plus another hour for links and its not far off.
Although most garages have a fixed charge for servicing often lower then the hourly rate it would normally occur.
The time drop links take depends on the age of the car and the state of the thread, have had to melt them off before now, it would be false to say that they should only ever take x amount of time as it varies massively for a simple air ratchet on each not, to having to spend an hour faffing around trying to free off one seized nut.