WHOA!!!! I'm not letting you get away with that one, Scipio!!!!!!!!!!!!!! Sheila and Jeremy had been bought up as brother and sister YEARS before either knew of their adoption. We adopteds may not "have hospital records and the like sitting around the house" we grew up in but here in England we're not so stuck in the dark ages that we don't have birth certificates -albeit, shortened versions- which give our names, sex and date of birth. Hospital of birth would be good but not necessary. I see my reflection therefore I am. Apologies to Descartes.
Many keep birth certificates in locations where they are easily accessible? Most people hide official government documents. Until I got my first job I was not even allowed to see my Social Security card and I have no idea when I was finally able to handle my birth certificate for the first time I think it was to get my driver's license when I was 17. All such documents were locked away. My wife took up where my mother left off, I have not seen my birth certificate or social security card in several years my wife locked them up in a safe along with hers, our marriage certificate, cash, jewelry or whatever else she has hidden away. I don't think I have ever seen any of my siblings' government records to this day.
The further children are in age the less likely they share interests together and will religiously know each other's ages. To complicate matters they were sent to boarding schools so were not even living together all the time till the oldest officially left home. Jeremy was 23 at the time of the murders and Sheila was 28. Saying she was 26 or 27 was not that far off and within the realm of reasonable error under all the circumstances. It appears he said 27 so was only off by a year.
It is highly unlikely that Jeremy told West 26 but West incorrectly recorded it as 27 yet correctly told Bonnett the 26. Much more likely is that he correctly recorded Jeremy saying 27 but screwed up when telling Bonnett or Bonnett somehow misheard him or misrecorded it.
The notion the 26 on Bonnett's log means Nevill must have phoned Bonnett is one of the most absurd arguments routinely made. Nevill getting his daughter's age 2 years wrong is rather unbelievable since parents seem to know their children's ages better than their own. The 26 is infinitely more likely an error between West and Bonnett than involving anyone else.