BIB - That's a mighty statement
But I fear it is said out of blind faith rather than reasoned judgement.
Last years Xmas DA came on the back of (what was seen by some) a weak 2nd series.
The Xmas ep this year follows on from a strong 3rd series.
EE is not rating as well as it has done of late - though there is no doubt the Xmas day ep will gather up it's current floating viewers on the day and I don't see the offerings elsewhere as strong enough to take them away.
However - I wouldn't be as blindly confident as you appear to be Dan - I think it's far more open than you care to acknowledge
And this is my reasoning as to why I think saying EastEnders will see a big rise on Christmas Day seems almost unlikely. Downton is hot going into Christmas and EastEnders isn't. I could be wrong of course but I can't see this rise coming.