Car key setting off alarm question

Factual Questions
1

Just bought a used car from a dealership, a 2 yr old seat leon diesel. My wife uses it in the main, and has a key with a couple of lock/unlock buttons on the fob. Works perfectly, when you lock the car an immobiliser is activated. My key OTOH, is just a key without any buttons, and it sets the car alarm off after 10 seconds if I don’t start the engine first. Just now I needed to get a box out of the boot; I had to unlock the door, get into the drivers seat, start the engine, switch off the engine, retrieve box, lock the car. What can be done to rectify this absurd situation?

I should add that the guy at the dealership is the type of insufferable dickhead who never wants to lift a finger for you once he’s done the deal. My wife had to go in to sort out some registration documents and mentioned this key business to him and was told that it was perfectly normal (?), given the immobiliser on the car.

2

Hope this isn’t a silly question, but is your key supposed to be the valet or similar key?

3

Not heard the term valet for a key - what does it mean? It’s meant to be a second key for a second driver.

4

I can’t tell you everything the valet key does, because every $#@% time we use valet parking I forget to bring it.

It’s basically a special key to give to a valet/parking attendant/whoever that limits the functionality of the car – things like not unlocking the glove box or driving over a certain speed or maybe disabling the eject button.