I tried:
<TABLE style="WIDTH: 243pt; BORDER-COLLAPSE: collapse" border=0 cellSpacing=0 cellPadding=0 width=324 x:str><COLGROUP><COL style="WIDTH: 81pt; mso-width-source: userset; mso-width-alt: 3949" span=3 width=108><TBODY><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; WIDTH: 81pt; HEIGHT: 12.75pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" class=xl24 height=17 width=108 align=right x:num="40137.375">20/11/2009 09:00</TD><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; WIDTH: 81pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" class=xl24 width=108 align=right x:num="40138.458333333336">21/11/2009 11:00</TD><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; WIDTH: 81pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" class=xl25 width=108 align=right x:num="1.0833333333357587" x:fmla="=B1-A1"></TD></TR></TBODY></TABLE>
had those set to dd-mm-yyyy hh:mm
and set the result cell to time and it comes out at 02:00:00
which is wrong as its 1 day and 2 hours?