Central Locking issue and no electrics for 5 minutes?

Hi,
I have a 06 207 1.6 HDI which has developed an intermittent fault which seems to be getting worse, every so often if you lock the car and go back to it after a few minutes and try to unlock it nothing happens, lights don't flash and no noise made, if you use the key to get inside the car and try the ignition then that's totally dead too, the only solution that we have found that seems to work at the moment is to get out of the car and try to lock/unlock the car, leave it for a few minutes then the indicators flash and the doors will either lock or unlock and alls back to normal. I'm hoping that the issue doesn't get to the point where it'll stop the car whilst driving!
If anyone can suggest anything to check or what could be failing then I'd be very grateful.
Apologies if this is posted in the wrong section.

Also we're having an issue with blue smoke on start up from cold and lumpy idle for a few seconds/until rev'd so not sure it that'll be linked? or if anyone knows what that could be?

Many thanks
Paul