i've lost my key at home somewhere !!! looked around for a couple days, but still not found. I know it's here somewhere but don't want to be with just one in the meantime.

How much to get replaced (it's the black one, I have a grey on - master)

Key will need cutting and coding to the vehicle and the missing key decoded - which is standard practise. I would say you're looking at about £200? The key will turn up and its not something I would suggest you worry about too much just yet. If I am not mistaken, then the grey key is not the Master - it is the valet key.

The grey key does all the functions of the black so I am ok for now, just wish the damn thing would make an appearance

I think the grey key is the "Valet" key and does not operate the glove compartment so you can leave personal items etc in there whilst the car is in for service.

I would worry that the key is in someone elses hands So you leave it near the front door? Are you sure you hav e left in the house but can't now find it? I'd be considering changing the locks if I wasn't 100% sure ................. and claiming off the house insurance.

The Grey key is not the master key by the way you should have 2 black keys (master) and grey key from new

Update - FOUND !! inside jacket pocket - the classic (the one i dont normally wear)

Sigh of relief !!!!!!!!!!!!

Nice ending

certainly was, I was beginning to wonder for a while !!

best advice is never use your master key keep it safe at home always use sub master or valet key, the reson been if you loose yor valet key and someone does find it and know its for your car you can delete the valet key with your master key via the car and also delete the remote as well.
The best thing is when you have deleted the key you can get a new key and programm it your self with the master key.

Hope this helps