Well I did...sort of.

Created setup response files by running setup -r 4 times
compiled (bat2exe) a batch file that does a setup -s in the right sequence and stuffed all this in a sfx winzip and it works like a charm.

The only downside to this approach is that the "package" is now around 40Mb whereas a neatly packaged version should be around 14Mb. I'll try the other suggested options (MSI & Wise/installshield) next week when all is quiet again.

Thank you all for the suggestions