Buyers Advocate

I am wanting to enter the property market as an investor. I have done a little of my own research through books, talking to people and obviously reading through various forum topics on this web page.
I live in a country area 3 hours from Melb, 6 from Sydney on the NSW,Vic border.
I have looked at and through a number of properties in our area and found generally they have good cash flow but not exactly great outlook for significant capital growth. I would like to buy in the city area mainly Melbourne, keep for the long term growth and hopefully continue build a portflio. Obviously living some distance away and having a very young family I do not have the time to make the track to Melb for long days searching, lookinf for properties that may be what I am looking for.
I am entertaining the thought of a buyers advocate.
Obviously they charge a fee, but as a positive, they aren’t linked to developers, don’t have any hidden agenda’s and they specialise in what they do.
Does anyone have any advice they could pass on about using this method? Do they charge a set fee and or a percentage based on purchase? Does anyone have any recommendations or referrals in the Melbourne area or elsewhere to make contact with?
I have googled a few to investigate and research.

BJR