Again thanks to all who replied on this subject. Much appreciated advice, particularly pit-falls to look out for. At the end of the day arrived home empty handed but the reason for this was to do with the body I was to pick up. It ws a B stock body andn I just wasn't happy with it. A few minor marks on the rear screen (which I could have lived with) and some functions not operating as I was expecting, an issue that was probably just down to settings, but for that kind of dough I wasn't prepared to take the chance, so new body on order. Not committed but I have my name on a 24-70 2.8 G ED. Appreciate the comments about size etc Rapscallion & jpw but having handled it, even on the d600, (which is incredibly light!) as a total package I do like the look and feel, it seems to work well and by all accounts seems to be a quality lens. So, no excuses!!!