Wow can't believe I missed this question, we did our research before we brought ours, if it is a smt when you open the drivers door you will hear the hydraulic pump start and you should only hear it for 20 sec or so, if you hear nothing than don't even bother! But note once the pump has built pressure you won't hear it every time so make sure before you test the car that no one has touch the car so you know for sure! Also ask what fluid they've used in the gearbox as I e heard people go use automatic gearbox oil and it stuffs up the gearbox, the gearbox is a manual! Also have a look under the car and it leaking a kind of red fluid it leaking hydraulic fluid so I'd walk away!
Also when starting up try putting it into first, it shouldn't start if it does than there's an issue!
Also test on flat surface and pop into gear and it shouldn't creep forward!
Well anything else don't hesitate to ask!
Have fun testing! But a least try a couple before buying as you will notice the good ones from the bad!