On my and dare I say every other 2.7 I have a round 3 inch ish valve like thing at top right of engine with a small inlet/outlet sticking out. No hose.
Anyone know what it is please ?
Also, mine is now starting without pressing the brake pedal first, is that normal ?

Don't know about the "valve" but my old 2007 2.7TDV6 i never had to press the brake to start it, think that only came in with the facelift in 2009 2015 L494 SDV6 3.0 HSE Dynamic
2006 L320 4.2 Supercharged
2009 BMW X5 M-Sport - Gone
2007 L320 2.7TDV6 SE Buckingham Blue - Gone
2011 Jaguar XFS 3.0V6 Diesel - Gone
2009 (59) L320 Facelift 3.0TDV6 HSE White Wrap - Gone
2008 BMW X5 M-Sport - Gone
2005 Audi A6 3.2V6 Quattro S-Line - Gone

Ah right. Mine is 2008.
The round valve thing is under the engine cover.