Eberspacher heater -- installation in Perth?

Have you contacted Waeco?
They are agents for them.

I would think that if you are reasonably familiar with tools you will probably be able to install it yourself.
I'm looking into getting one in the future and during my research I've come across plenty that have had problems not with the actual unit but with the installation done by the installers, supposedly experts.
Seems very similar to fridge installations in vans and motorhomes, there is a correct way and the way "most" are installed ie: quickly and cheaply.
The biggest source of problems seem to be the location/mounting of the inline fuel pump and the routing of intake and exhaust piping. Most problems with noise from the pump and unit are related to its location in relation to the bed and the non installation of the appropriate sound proofing/mufflers to intake and exhaust.
The exhaust seems to cause external noise to other campers if not installed correctly, which seems to be the majority!
We recently camped about 50 metres away from a Kimberley Karavan at a quiet bush location and the exhaust was clearly audible to us. The owner commented that yes it was noisy and was audible inside as well.

Try Care A Van in Cannington.They installed another brand in my Kimberly Kamper, but the installation should be very similar.
http://www.careavan.com.au/