Electrical nightmare

[flowing1]

Can anybody help with this problem I'm having...
I have a P reg 1.4 16v polo, I have been experiencing some problems the last week. When I drive the car after a while all power goes on the car causing total power loss and after a minute of turning the ignition a few times the ignition lights come back on and i can start the car no worries. This has happened twice on the motorway now and what happens then is i cant indicate or anything but after it has drifted the ignition comes back straight way.. very strange.. is it caused by the alternater or battery, or is it something else?

[geeforty]

If you wiggle the key a bit when the engine is running does it conk out then - could be a faulty ignition switch, or faulty ECU relay (switches the power to the ECU)  I think it may be the third relay from the left on the upper row (RELAY 3)  sometimes has 109 printed on it

Also check the battery terminals are all tight, and the earth wires from the battery to body and engine are tight