[Webasto thermo top C in a TD5]

I have been reading this post for a while. I have now brought a Webasto thermo Top c for my 2006 Defender 110.

I have two questions about fitting it. I have air con and where the heater would normally be fitted there is a great thick pipe for the air con system. Is this in the way ?

Second could someone send me the Defender Specific instructions that people here write about.

Thanks

Simon.