Parking in Newark

[Rich1973]

My friends and I are going away for a few days in October by Eurostar. We will be travelling to London from Newark. I have had a look at parking, and there is a NCP next to the station.
We will be going friday and coming back monday. I have noticed that weekly parking is £25 and by the day is £9. I don't know if weekly is mon-sun or a 7 day period. Either way the difference is only a few quid.
I just wondered if anybody uses this carpark for overnight parking and if it is OK?

Richard