Docker failing to start during installation of Zenoss 5.1

I have been folllwoing the Zenoss 5.1 planning and instllation guides to setup a server. I have got to page 13 where docker has been configured and is to be restarted before installing Zenoss. However I have a problem with Docker not starting. I have two issues that I see;

1. the first time I try to restart the docker using "systemctl restart docker", it fails and the error code is;

level=debug msg="[devmapper] CreateDevice(poolName=/dev/mapper/docker-docker--pool, deviceID=1)"

level=debug msg="Registering device (id 1) with FS size 107374182400"

level=debug msg="registerDevice(1, )"

level=debug msg="Creating filesystem on base device-mapper thin volume"

level=debug msg="activateDeviceIfNeeded()"

docker.service: main process exited, code=exited, status=2/INVALIDARGUMENT

2. the install guide states that it may fial the first time and needs to be restarted a few times due to the mount not being ready. If I restart multiple times I get anther issue;

level=debug msg="[devmapper] deactivateDevice END()"

level=debug msg="Error deactivating device: Device is Busy"

level=debug msg="devmapper: DeleteDevice(hash= syncDelete=true) END"

level=debug msg="Error device setupBaseImage: Device is Busy"

level=fatal msg="Error starting daemon: error initializing graphdriver: Device is Busy"

docker.service: main process exited, code=exited, status=1/FAILURE

Sometimes I can restart without the second error (which I beleive is a problem with the previous mount not being released) but I still get the first error in call cases.

I have read a few articles about what the problem can be, but I've not found a solution and I have followed all the steps in the setup guide. Note that I have also removed the ( -H fd:// ) form the startup options as I've read that this causes issues with a socket error.

Any pointers on debuginng this would be appreciated.

Info: Centos 7.1 / Zenoss 5.1