Hopefully the car will cooperate with your technician. It sounds a lot like an intermittant resistance in the starter circuit.
This could be anywhere between the individual cells of the battery to the armature of the starter. Very simple to trace when the problem exists. Almost impossible when it doesn't.
The fact that your problem occured after some driving could lay blame on the starter as armature problems often occur hot.
Bosch Master, ASE Master, L1
33 years MB technician