Well - let's be a bit more explicit and to be clear for future readers ... here was my wife's timeline:
March 2007-April 2007 - in UK as tourist
October 2007 - December 2007 - in UK as tourist
Jan 2008 - April 2008 - in UK as fiancee
April 2008 - convert to Spouse
March 2010 (28 days before expiry) - convert to ILR
April 1st 2010 - Apply for citizenship on basis of presence in April 2007
May 2010 - citizenship granted
Mid June 2010 - Ceremony attended
For something in writing - check out the guidance:
http://ukba.homeoffice.gov.uk/siteconte ... chapter18/
Look at the residence requirements PDF - especially at 2.3.
The important thing to realise is that you *must not* breach the days away requirement. There is *discretion* to allow more days away for work - but it is only discretion - it isn't a requirement that they do. Read section 4 in the same PDF carefully to see when they can apply the discretion.
M.