HTML help files missing for some packages

Thanks, Johannes. Installing r-base-html fixed the problem. And 
APT::Install-Recommends and Aptitude::Recommends-Important are both 
"false". Presumably the default in Mint (and perhaps Ubuntu) is 
different from that in Debian. There may be a good reason for that, but 
I will take it up with the Mint developers.

Thanks for your help.

Paul