I'm a licensed installer in Sydney.
Mate, I can't help you out as much as a I would like to, but I can offer advice.
Here in Bad old Sh1tney town, its common practice. Basically bend over. Your only choice is how much lube......
Good companys (and yes I claim to be one
) give an up front final cost involving all metering etc etc.
What I write on the bottom of a contract is final all you have to pay price.
If they are trying it on, tell them to get far away!
Besides the requirement for a harness is based on height above ground, not pitch.
They should have them on anyway even if its a flat roof. Seems to me they just want more coin.
Can I be so bold as to ask what you were quoted and for what size system?
If you don't want to say, pm me and I can tell you if its good or not.
I can also get some names of decent installers in your area as I have a mate up in sunnyland who is in the large scale industry and knows plenty people.
Getting back to your point.
Tell them to get stuffed and get a fair price from an honest sparky, despite what the myswag leccie section says, there are some good ones available.
Just ask Symon....
PM me if you need more help.
Brian