Hi Sixdays300, if you mean me then I have a VF Calais V, which comes with 19" wheels (regardless of which motor is fitted). Mine came with a full size alloy spare, which was one of the reasons that persuaded me to buy that particular car, as others could have either an inflation kit or an 18" steel emergency spare, depending on model year and dealer generosity (or lack of).
The VF Calais (non-V version) comes with 18" wheels, again regardless of number of cylinders. Depending on model year it could have an inflation kit, an 18" steel emergency spare or a full size alloy.
From your 'Ride' description you have a VE Calais, which in stock form has 17" alloys with a 17" steel spare. It would seem someone has swapped your original spare for a 16" one, which, as you rightly point out, is useless to you. If you've only just bought the car from a dealer they should be able to source the correct 17" wheel for you, and swap it for the 16" one.