Ah, OK. I do think, if Above Suspicion gets > 7m like series 1, then they should maybe try Monday and Tuesday shows again, especially if it in the short term helps Tuesday's out. But as you rightly say, Law and Order does need to go somewhere. Maybe that'll go on Friday's? IIRC, Trial and Retribution did well earlier this year with > 5m against BBC's comedy hour.
One final bit from me, here's the Top 10 Overnights for this decade, and what The X Factor needs to get into the top 10:
Most Watched Programmes of the decade (overnights)
1 20.3m (73%) Only Fools and Horses (BBC1, 25/12/01)
2 18.9m (70%) Euro 2004: England v Portugal (BBC1, 24/06/04)
3 17.9m (69%) EastEnders (BBC1, 05/04/01)
4 17.6m (61%) Coronation Street (ITV1, 24/02/03)
5 17.3m (68%) Britain's Got Talent (ITV1, 30/05/09)
6 15.1m (56%) Tonight Special: Millionaire (21/04/03)
7 14.4m (58%) World Cup 2006: England v Sweden (ITV1, 20/06/06)
8 14.3m (53%) Wallace and Gromit: A Matter of Loaf and Death (BBC1, 25/12/08)
Note: Only the top rating per programme is used. One rating per football tournament
I think tonight's show will slot in either 6th or 7th. There's quite a big gap between 5th and 6th (2.1m), so it may not actually move up any positions in terms of the above chart - saying that though, if tonight's show gets ~15m then tomorrow could get 17m.
Tonight depends on how much the first 45 minutes is dented by Strictly, I suspect Strictly may be dented to about 6/7m while The X Factor will have 12/13m in the clash.
The peak will also be interesting - and maybe give us a clue as to what the average will be tomorrow.
Guess half of the puzzle will be revealed with a red banner at 9:35am tomorrow.

(I think we'll have a banner - there was one IIRC for BGT?!)