Just for info. Fabia 2007. Over the past three years I've replaced driver's door lock and both rear door locks due to them failing to release. Fortunately with all locks they could be 'encouraged' to release by banging on the door near the lock while operating the key fob. Bit of a pain as the internal panel is rivetted in place. I examined the old locks and the actual motor seems clean and spins ok. It seems to be an intermittent failure in the plastic cam driven by the motor thread. Also the micro switch cam was worn on one of the locks which affected tailgate opening and interior lights. Replaced with locks for about £22 off a well known auction site.

14 hours ago, billwin said:

Also the micro switch cam was worn

 

Yeah, it's a metal cam with a thin coating of plastic which gets shredded by the microswitch button. I stripped the plastic off my cam, so my replacement microswitch just runs on the metal of the cam, but I grease it with silicone grease every now and then through the door latch hole. Still working ten years later. Relacement switch I used was a Burgess V4NSUL.