I'd say that it would be cheaper to organise driveway people separately to everything else - concreters are specialists and so a landscaper may not be the best qualified. if they organise it for you - they'll probably add 20% to the price to make some profit.
Did you ask ecodesign the cost for doing the landscaping?
I got a full quote from ecodesign recently, including pool design etc. and there are sooooo many things in that quote which they won't put a price on, was not happy in the slightest. Plus yes, they project manage the build after getting quotes from numerous places and picking who they would like to do the work. Their price for project management is a set fee plus 5% of what the contractor cost works out to be.
We are going to try this place next
http://www.exterior.com.au/
Their designs seem to be aligned with what we want and they're local for us.