Laguna II GPS and clock

[jeffo]

I have a new Laguna with a factory supplied sat/nav but the clock and satelite icon do not always work [:(!].
The GPS arial has been replaced by Renault and it has been back 4 times but the problem is still there intermittantly.
The main irratation is the CLOCK, it resets to 12:00 at the start of some journeys and will not correct itself for the remainder of the journey. (The car is parked outside all the time so it is not shielded from the GPS signal)
Has any had a similar problem and how is it fixed?