Just want to know if there's any reason why i shouldn't connect a pair of 4000's to a BC1 via the headphone out and line in?

It's just that the TV has no powerlink (the upgrade would be over AUS$1000, which is insane). :(

Is there a loss of sound quality at all connecting Beolabs via line inputs directly from a headphone jack on a BeoVision?

Thanks! 

Hi Dave, this should work fine.

OK, so it's maybe not an ideal approach electrically, but it should give you the result you need.  I can't immediately think of an alternative solution with the equipment you have.  You need a cable with a 3.5mm TRS headphone plug at one end and two RCA (also known as phono) plugs at the other end.  The sound quality won't suffer and you won't damage the Beolab 4000's (just turn the BeoCenter 1 volume down low to start with!).  Ensure that everything is switched off when you connect the cables and switch the 4000's to "Line" input mode.

Best regards,

Steve.