Thanks everyone (Adampr, elekie&a/c doctor, skidpan) all your comments are relevant and useful. If it was a high cost Range Rover or BMW etc it would be a no brainer and an immobiliser would have already been fitted ASAP. I was offered top-up insurance to new car value but it was £350+ from memory for 3 yrs only & then it would need to be renewed - an immobiliser would be a single cost for life so would be better value & I wouldn't lose the car unless it was taken on some sort of low-loader/trailer. I tried a Disklok but there is a flat surface on the bottom of the steering wheel causing it to flop around & it could probably be easily prised off at this point with very little effort. According to Google; disabling the keyless entry seems to be possible but it might not be very practical - there might be something with the key fob buttons but I may need to ask Kia about this. It's my first new baby so am probably more paranoid than I should be ...

Thanks Adampr, curtain peeping has become the norm these last few days. I will have a look at the Infotainment and take a closer read of the car manual. I've just been given a contact number via Kia chat for their Customer Service Team 0332 202 2990 and may contact them tomorrow when they are open again. At the moment, I have the keys wrapped in tinfoil & this is very effective at blocking signal blocking till I settle on a more permanent solution.

Thanks edithgow; one of my friends said he uses a chain around the steering wheel of his GTO & ties it to the door handle, I haven't looked under the dash yet but will do so in a short while.