Garages usually find faults and then tell you that your car has failed the MOT and it will cost £xxx to fix. If you get them to fix the faults they normally redo the MOT for Free. As these were minor faults and probably took 30secs to fix they may have fixed them for nothing and they passed it rather than wait around for you to agree and them waste an engineers time performing the retest at a later date.
Sounds like they failed the car on the headlamp aim, very common
They have then adjusted the headlamp aim, and then passed the car
If you have the MoT certificate then the garage should really have explained that!
Remember though the MoT only certifies a vehicles roadworthiness for one day!
The certificate itself is valid for 12 months (or 12 months plus the renewal period if the MoT was carried out within 30 days before expiry)