'm enjoying watching 'Heir Hunters' too, but years ago I used to be entertained by Fraser and Fraser (and the other probate firms) in a different way.
Before the Internet, and even before film and fiche versions of the GRO Indexes were widely available, firms like Frasers had no option but to use the index books in St Catherine's House. I used to see them there in the 80s and 90s - and it's fun now seeing many familiar faces on TV.
Because there was only one set of indexes that everyone had to use, it got very interesting when firms were in competition on a big case. They could be literally shoulder to shoulder with a competitor working on the same case, all desperate to keep their notes hidden from each other. One researcher I knew was an accomplished linguist, and used to make notes in Russian, so that the competition couldn't read them, and another once left a shorthand pad of 'decoy notes' in the pub that they all used! All hell would break loose if someone mislaid their real notes, though. If someone found an entry they were looking for, they might memorise the details and carry on looking in a few more volumes in case a competitor was watching.
It was much less fun when big firms like Frasers started buying their own copies of the indexes, and doing their searching in-house (although at least it left more room for the rest of us to get at the index books).
Incidentally, it was a spin-off from heir hunting that led to some online BMD indexes; one of the other large firms, Title Research, had also bought a set of the indexes and went a step further in scanning and digitising them for their own use. They went on to make these available on the website, 1837online, which eventually grew into Findmypast.
Mean_genie
