Obby - I'd love to answer your question, but having just returned from a Time Out for mentioning the contents of a couple of the reports which I have, including the autopsy report, I can't really answer directly.
However, I can answer hypothetically - a finding that MAY have been a subdural haematoma (very small, and certainly not clearly one) would be unlikely to cause death. Some people have chronic subdurals for years, especially those prone to falls, or repeated head blows (eg boxers or drunks).
It is possible that a blow to the head can cause unconsciousness (eg the KO blow in boxing or Mixed Martial Arts) of course, and usually these don't leave any signs or problems apart from concussion afterwards.
If a hypothetical subdural haematoma were to be found, it may have been a more chronic one - older, perhaps related to previous head trauma.
Of more immediate concern would be an EXTRAdural haematoma - outside the dura, and this is usually an arterial bleed, (subdurals are almost always venous bleeding), causing much higher pressures in the haematoma, and hence people can die from these quite quickly. However, I should stress that when the autopsy findings were aired in court at the second bail hearing, these was no mention of an extradural haematoma.
I'm speaking purely hypothetically here, of course, as you asked the question, but in general, a blow to the head can render a person unconscious without there being a subdural haematoma necessarily. Or a skull fracture, unless a weapon is used - it's very hard to fracture a skull with a fist or even a foot - unless the victim falls onto something hard and the fall fractures it. That's the basis of the "One Blow Can Kill" message.
