Sedona wont start

[neilthecat99]

Forgive me if there is an existing post for my problem, had a good look and couldn't spot one.

I have a Kia Sedona 2000, 2.9 turbo diesel model and just recently have had problems starting it. The engine does not turn over and all you hear is a click, after a number of attempts it fires in to life. It doesn't appear to be the immobiliser as this cuts in once I've managed to start it if I tried starting with the immob light still flashing. At first it would take about 5 turns to fire up but lately it's about 15-20, but in some instances it fires up first turn of the key. It's most confusing but I'd appreciate some help before I take it in to a garage and get charged for any unnecessary work.
Thanks for looking.