Looks like its a case of putting down to "bloody computer"
anyway as theres no real solution to the problem other than an automatic windows update, I may as well share my set up just in case anyone else stumbles upon this looking for help:
Set up: Thomson TG582n ADSL2+ Router ( also works with the cable/fibre version) The router is downstairs connected to the (BT NTE5 ) Master socket, the target PC is in another room, on another floor, connected to the router via homeplugs
Motherrboard/Bios settings Asus M5A99X EVO R2 ( the easy bit)
Go to Advanced in the Bios and set power on by PME devices as enabled
TG582n Router settings - guide here Link Removed
PC settings in device manager, under Advanced set wake on magic patern to on, and power manager tick all the boxes, even the one that says turn off device to save power