Who can repair my Vauxhall Zafira's central locking system?

I have a Vauxhall Zafira on a 55 plate and I can only open the drivers door with the key, while the rear hatch won't even lock. I checked all the fuses and one had blown, so I changed it, but it still...

What's causing my Audi A3's electric windows and central locking to malfunction?

The electric windows on my Audi A3 V-reg are only working on one side. I can't see anything wrong with it but also the central locking only opens the driver's door, and then the alarm goes off.

Where can I get a replacement central locking unit for my Mercedes-Benz A-Class?

On the 10th of this month I bought a 10 year old A-Class Mercedes-Benz from a local dealer. Within a couple of days I found that the central locking unit did not always work - then it stopped working altogether....