Developer and reasonable delays

Scenario:
Developer splits block, sells as H&L. Sells block A a month before block B. Buyer of block A knows what he wants and moves quickly - finance/modifications etc and expects them to crack right on.
Both builds start in unison four months after block A is sold.

Is the developer liable to buyer of block A for holding costs if its proven they delayed the build?

 

What proof and was it reasonably forseeable ? If the vendor hasnt given a warranty about timing I cant see a issue. They may be too busy to schedule one build vs another. All people involved in building know delays are inevitable in OTP sales. Council may have held one up for the "in-line" approval for streetscape and civils etc. Builder would be crazy to pay for sewer connection / slabs etc with two distinct jobs v's one job split on two lots.

If time was of the essence what clauses were in the contract ?

 

I have never bought this way before but had a friend ask so thought id throw it out there. All good points.