I have several pieces of Clegg gear, and it's all very high quality stuff. Unfortunately, I've never owned a Venus, so I can't tell you much about aligning one. I did find the manual on the web (
http://www.radiomanual.info/schemi/Surplus_Radioamateur/Clegg_Venus_user.pdf), but it's a very poor scan and the schematic is nearly unreadable. In any event, the version of the manual that I found gives no alignment instructions, anyway.
All I can suggest is that you look at the alignment process for other rigs that use similar circuitry, and use a little intuitive reverse-engineering. You might look around for a manual other than the one I referenced; maybe another edition might contain alignment instructions.