Warranty on my Leon ended in Sept '17. Prior to that I called a local SEAT garage to ask about (a little) moisture in rear light cluster to be told it's normal in vented light units. Seemed odd to me, but hey ho. Sure enough, the next service (Oct, after end of warranty) a different garage pointed out the moisture and quoted £200 to replace the light unit! So, is the moisture a concern (2nd place were talking about potential concerns should water find its way into electrical system)? What should I be looking to pay to replace the unit if I need to and is it an easy job to do myself?