Upgraded my amstrad sky hd box 780c-uk to 1tb hdd 2 weeks ago.Used a samsung spinpoint f3 hd103sj 1tb hdd (http://www.ebuyer.com/product/173804) £61.used the guides on several sites and found it quite easy,did have to reopen box several days later to set hdd to quiet on aam,default setting on hdd was a bit noisey (crystaldiskinfo 3.5.6).found the new hdd works well and is very quiet(recording 2 hd channels and playing 1 recorded hd program at same time).used Copy+ version 1.2.0.6 ,laptop and usb to sata cable with power (ebay £5.99)to set up hdd .chose this samsung hdd due to similar spec to orginal wd hdd.
Update- 3 months after 1tb hdd upgrade, sky hd and new hdd still working with no problems (no failed recording,no standby or power problems, epg running at normal speed and hdd quiet)