Move client install as part of TS

We have a captured image that I'm deploying as our standard SOE, everything is fine, working well.

We have a couple of dozen PC's that are available for use by the public and are locked down using Faronics DeepFreeze.

I've got the DeepFreeze side worked our fine, create a secondary partition, keep that unfrozen etc.

What I'm stuck on is trying to do is have the SCCM client moved to the secondary partition as part of the TS. I've tried the following:

1. Create a new SCCM client package with the correct parameters of CCMINSTALLDIR andSMSCACHEDIR 

2. Use the parameters section of the TS step

3. Write a powershell script that triggers an uninstall / reinstall using SMSTSPostAction

I'm at my wits end.

It seems that because the CCM client is already installed (due to the capture) any other installation just installs it back to the same place.

Anyone have any experience with this? 

Thanks in advance!