Warning light stuck on again!

Had the above warning light come on last week ,( looks like an engine block),so took car to Skoda.They came up with Fault Code P0674 ( Cylinder 4 glow plug circuit fault )

They cleared it and checked it , and was happy it was probably just a glitch that caused it. It came back on again yesterday. Only done about 40 milesin it.

Took it to my local garage and they have got the same code again,but want it back again next week to have a proper look because they were short staffed and managed to just check it out for me.

Any ideas what might be causing it? Car is a 2006 VRS.Ok to carry on driving it locally?

Thanks