And I added the tags for EuroAristo, England, and medieval to get your post noticed!
When I search Google for "Richard Berkeley Allan" I basically get only two results, one is this question, and the other is a Geni profile which doesn't cite any sources.
To me, that indicates that Richard Berkeley Allan, probably never existed. The fact that he has the last name Allan, instead of Berkeley also is a strong indication that perhaps someone at some point has tried to forge a connection with an English family to enable an longer genealogy.
Lastly the current profile for James de Berkeley appears to be using good sources and again there is no attachment to an Elizabeth FitzAlan or a son Richard.