Drying time of large roughcast render patch?

[Ron66]

Hi
New to the forum and looking for advice. Builder roughcast a 8ft wide x 2.5ft patch that had fallen off my garden wall 48 hrs ago. Cracks have now appeared and it still feels damp, should I cover it in plastic sheeting to prevent rain getting into cracks and help it to dry. I can't be bothered hassle of getting Builder back out so thought perhaps once dried I could infill the cracks? Any advice would be appreciated.They
Ron

 

[blup]

Is it drying out too quickly, and what was the state of the wall before, any before and after pics?

Blup

 

[blup]

You may get more answers if post is transferred to building forum

Blup