Scoda roomster scout 1.6 tdi

Hi everyone I’m having electrical problems with my car . A year ago the boot wire split on tail gate and blew the main controller box all in all was just under a £1000 to repair .

The last month similar pattern is emerging so I knew the boot wires had either broken again . I now have another problem when I’m driving and have lights on .

If I turn the key ignition off and leave car lights on . The car still runs engine )!!

Then if I switch lights off the car engine will stop just like using keys !?! 

I have taken it to Scoda it was the wires in the boot shabby job last time from another garage they just joint them together with a plastic joint in middle so earth is hanging out and still broke . This is being replaced .

Scoda are saying it’s probably the ignition barrel that needs changing regarding my lights issue . So they are charging me £610 to do this on Monday . 

My concern is has anyone had this problem and would it be linked to a ignition barrel ?!? It is a bit stiff to turn key now and then but I just don’t trust any garage no more !

Any help or info would be appreciated thanks Michelle