Andy Wade wrote:

There are actually up to *four* "conversion factors" which are now being
confused in this thread:
(explanation snipped)

We are not worthy ;-)

I hadn't realised the volume conversion factor was a constant. And was
mixing it up with the calorific value, which is variable (by up to 15%
I found, surprisingly - probably due to the %age of C2 and higher
hydrocarbons).

--
"Politeness, n: The most acceptable hypocrisy."