The battle for Big Brother continues with the Seven Network now saying it will “participate” in the process, a move which has got media buyers confused because it represents such a dramatic move away from the network’s successful “heartland” approach.

The Ten Network is currently locked in difficult talks with Endermol Southern Star over a new series of BB in 2008.

Ten is unhappy with Endermol Southern Star and has already made that clear by shifting production of the local version of So You Think You Can Dance to rival Fremantlemedia, which also produces Australian Idol. That has not made for fruitful negotiations and now Seven and Nine are trying to drive the price higher for Ten.

One Sydney report said Seven was preparing a $40 million bid for BB, but that doesn’t sit well with assurances to analysts recently that it was not looking to boost costs past a rise of 10% (taking into account the extra costs of the AFL and the V8 Supercars or around 3% excluding those two programming areas).

Buying BB also won’t fit well with its so-called “heartland” approach of aiming its programming at the 25 to 54 groups, while trying to pick up younger viewers in 18 to 49. The 18 to 49 group is a key demographic for Ten, but Big Brother is aimed more at the 16 to 39s. Big Brother doesn’t get much support from viewers above 30 years of age.

And Seven doesn’t have a regular timeslot for BB: 7pm is out because of Home And Away. 9.30pm weeknights is a weak spot for Seven on most nights and putting it there would enable more risqué material to be shown, but that would dry the ire of Christian groups, conservative politicians and damage the network’s standing among viewers in its “heartland”.

The betting is that Ten will keep BB at a higher price because its 100 hours of programming, extra profile and a lot of free publicity which would cost a lot to replace.