Vanilla Grav 500 internal error

I can get grav to work locally. But with my host Im getting 500 internal server errors

I went into your cPanel > PHP Selector > PHP options and turned on error reporting.

Your missing files:

Fatal error: Uncaught RuntimeException: Opening file for writing failed on error fopen(/home/simonmor/public_html/cache/compiled/blueprints/master-simo nmorrison.com.au.php): failed to open stream: Permission denied in /home/simonmor/public_html/vendor/rockettheme/toolbox/File/src/File.ph p:202 Stack trace: #0 /home/simonmor/public_html/vendor/rockettheme/toolbox/File/src/File.ph p(316): RocketTheme\Toolbox\File\File->lock() #1 /home/simonmor/public_html/vendor/rockettheme/toolbox/File/src/PhpFile .php(31): RocketTheme\Toolbox\File\File->save(Array) #2 /home/simonmor/public_html/system/src/Grav/Common/Config/CompiledBase. php(236): RocketTheme\Toolbox\File\PhpFile->save(Array) #3 /home/simonmor/public_html/system/src/Grav/Common/Config/CompiledBase. php(100): Grav\Common\Config\CompiledBase->saveCompiledFile('/home/simonmor/...' ) #4 /home/simonmor/public_html/system/src/Grav/Comm on/Service/ConfigServic eProvider.php(65): Grav\Common\Config\CompiledBase->load() #5 /home/simonmor/public_html/system/src/Grav/Common/Service/ConfigSe in /home/simonmor/public_html/vendor/rockettheme/toolbox/File/src/File.ph p on line 202

[root@cp10 public_html]# ls -all /home/simonmor/public_html/cache/compiled/blueprints/master-simonmorri son.com.au.php
ls: cannot access /home/simonmor/public_html/cache/compiled/blueprints/master-simonmorri son.com.au.php: No such file or directory

Really have no idea what Im doing differently. Host has apache and php 5.5+

First step is to check out the items in this permissions document

permissions look ok. all the files are 664 all the folders are 775.

i've tweaked the .htaccess to
RewriteBase /grav-admin
reflecting the base install in the subfolder in my designated public_html

-cpanel reports the error as:
[Thu Aug 18 00:55:58.734131 2016] [:error] [pid 157625] [client 220.253.177.21:58392] SoftException in Application.cpp:261: File "/home/simonmor/public_html/grav-admin/index.php" is writeable by group

-refreshing the page gives a 500 server error.

Your server might have security restrictions to stop things running with Group access. Where are you hosted? And are you open to changing provider?

Im with Aussiehosts. One of there support staff, say grav is supported. And there is an install script. So today Im trying it out...i'll let you know.