is it possible to retro fit the climatronic unit in place of the climatic

possible, yes but very expensive as you'll need loads of parts.

This was covered a few weeks ago on the Seat forum, and to change from climatic to climatronic was quoted to one member in the region of £4000.

Mike

Just a taster of the work that is required

http://furmanka.blogspot.com/2008/12/mk5-klimatronik-climatronic.html

its for a golf Mk5 but would be very similar for the Octavia Mk2