Thanks for that, I look forward to Mr Finney's reply.
About the negative G cutout, in this film starting at about 24:00 Douglas Bader, Robert Stanford-Tuck and Sir Stanley Hooker explain about the pitfalls of the gravity fed carburettor and why it is was used instead of a direct fuel injection system such as those found on the 109.
http://www.bbc.co.uk/archive/battleo...in/11405.shtml
If you're outside of Britain, you might not be able to view the film...sorry.