Having a strange anomaly tonight with BBC1 HD and BBC HD in that both are having severe picture loss but still have sound. Teletext & red button operation are fine.
ITV HD and C4HD (non freesat mode) are both perfect.
Did a factory reset / re-scan but no change.
Also had scheduled recordings of "Waking the dead" on BBC1 HD on Sunday & Monday and both were useless.
Other ITV HD recordings were fine.
BBC1 and 2 SD reception is fine.....
Are there problems with 10847V signals?
Anyone got any ideas?

Both 100%/100% from my lnb. Have you some interference freom something like a wifi router (especiall BT-Homehubs).

What does diagnostics report ?

Thanks Graham, but all is suddenly now OK (ps I'm in Spain at the moment - coming back later today!).
Anyway, the Sagem's diagnostics showed signal "strength" the same, but signal "quality" much reduced on these two channels.
I therefore did a total factory reset & HDD format, powered down for 1 hour and "re - installed" the unit this morning. At first nothing appeared to be different, but after about 11.30 local time (10.30 UK) the signal quality suddenly went up to 100% on both BBC HD channels.Spooooky, eh?
Now all is OK.
By the way we did have four short power cuts the other day (nothing unusual over here - will be glad to get back with the Sagem (dtr 94500 pvr) & check it again - it does seem to be a pretty tough unit considering the power & reception "issues" we get in Spain.