I have recently carried out an
change and filters on my laguna 1.9dci. The service interval for the
change is 18k, but when I drained the old
it was in very bad condition. I do around 120 motorway miles a day so I guess 18k inervals maybe ok, but I have heard the dci engines should be changed every year or 9-12k miles when doing frequent short trips.
The service costed me as follows:-
Air filter £8
Pollen/cabin filter £14
I would maybe wait until 9k miles and then get it serviced with an independent dealer, or just a local garage.
To be honest changing the filters is dead easy. I brought my filter from german swedish and french car parts which were fairly cheap, they included a step be step guide on how to fit the filters.
Hope this information helps.