There are always special challenges with each person as it relates to connect. I'll mention the ones I think you'll encounter, although it's hard to say unless you roll up your sleeves and dig in.
1) Records for England are only available as recent as the 1911 Census. There are some additional indicators and hints you can follow that can open up certain avenues, but they're challenging and just take patience and persistence to figure out. Since he was born in 1942, finding specific Cenus, Birth, Marriage, etc. records can be challenging, but as mentioned above, not entirely impossible.
2) The key to connecting him will lie in two directions - ancestors and marriages. His parents are mentioned in Wikipedia (Alec Challis and Joan Harden) so at least the parents are a good clue to start with. From a marriage standpoint, Wikipedia shows him married 4 times and at least 2 times to others who have Wikipedia articles, and one who appears that she might have previously had one. So with those clues, you have some possibility of either encountering an existing profile that may be connected, or chasing his family up the tree to a potential connection.
3) Ethnicelebs.com is a good resource to hunt for clues. Sometimes they get it wrong, so never just blindly accept someone else's genealogical research without double-checking it first, but they do point to other people's research and occasionally they'll point at WikiTree. In his case, I did not find a genealogy there that they're tracking for him.
4) FamilySearch will often have a tree started as well, but again, double-check their research. Since he recently passed, you would probably have to start with the parents, so seek an Alec and Joan Challis from England and if you find one, dig deeper to make sure they're the right ones before making assumptions.
5) And finally, news articles, Google searches, and other internet resources will often drop clues about brothers, sisters, cousins, aunts, uncles, or other family members that lead you to additional family you can seek for a connection. Books like biographies can be helpful as well.
Usually once I get a tree going, and there are potential connection sources from family members, I'll chase around the tree for a connection and see what I can come up with.
As it relates to him, I would expect him to be challenging to connect, but if you can find relatives that extend beyond the current 1911 Census barrier, then you've got a decent chance of finding a connection. Good luck.
