What connections are on the Sky+ box? 2 SCART and an RF?
What's on the 850 - HDMI or just component/SCART?
On that assumption - here goes:
Sky+ (SCART) TV.
Sky+ (SCART) XS32 In
Sky+ (RF) XS32
XS32 (RF) TV
XS32 (Component) TV
HD850 (HDMI-DVI cable) TV or HD850 (Component) TV
HD850 (coax/optical) Sharp surround
XS32 (optical/coax) Sharp surround
You might not get away with the 2 DVDs being connected to the Sharp (digitally) and on, unless you can choose the type of input for each on the system. If you can only choose digital or other inputs, then you'll need to wire up one of them via one of the analog inputs.