I don't know which particular online pedigrees you are referring to, but I would suggest that you need not trust any of them unless they are properly sourced. If they are, you can check the sources and see if you think the pedigrees are right. The printed word is not infallible just because it is printed, whether in a book or on a web-site - if "printing" is an allowable word in that context! I have seen a number of trees on a well-known subscription site which are demonstrably wrong in some details.
As for the difficulties of your area, it is just as bad in Glamorgan, as I well know, my mother being from the Rhondda! You sre not alone.