192.com only has the 'edited' electoral rolls. Since many (probably most?) people tick the box on the electoral registration form which removes their name from the edited roll, there's no guarantee that they'll appear on 192.com. (Further, 192.com isn't cheap).
Assuming that the person has actually registered to vote (which some people don't bother to do and others, such as some foreign nationals, aren't eligible to do anyway) their name
will appear on the full electoral roll but that's not available in electronic form (other than to the police, the security services and credit reference agencies). The only way to see that is to visit the relevant local council office (where the law requires that the full electoral rolls must be available for inspection by anyone). However, since the registers are arranged in street order (and not in alphabetical order of surnames) it can be a long job going through them if you only know a very general area. (e.g. it wouldn't take long to view the names of everyone registered in a small village but if you only know that someone lives in, say, Birmingham, it could take days to search through all of the registers).
Of course it's always worth checking the Phone Book, which is online here:
http://www.thephonebook.bt.com/publisha.content/en/index.publisha#
However, since many (most?) residential numbers are now ex-directory, there's no guarantee of finding the person you're seeking.
There are other ways of seeking people who might want to be found (such as appeals via local newspapers or local radio) but, because your post appears in the 'civil law' section, I suspect that they're not relevant here as you're probably pursuing a debt and seeking someone who'd rather that they weren't found by you anyway.