After having a drunk neanderthal in the car last night, the internal front passenger door handle is now in two separate distinct parts.

 

Although what's left of the lever still moves, it's clicking against something and won't open the door from the inside. Until I get the door panel off I won't know what further damage has been caused, but how easy is it to replace and can anyone suggest best method/pitfalls to look out for?

Yep door card off, quite a good guide here:

 

http://www.briskoda.net/forums/topic/390360-guide-removing-front-door-card-octavia-mk3-including-changing-tweeter-capacitor-for-better-sound/