Vehicle ignition system, alternatives to standard key?

hi all,
my question involves the ignition system for a vauxhall brava pick up truk with a 2.5ltr diesel.

it was stolen a few months ago from our local village however the genius thieves drove it 3 miles and ended up ditching in our next door neighbours drive, they took the keys with them when they left the vehicle and i dont have a spare set, it has remote central locking which is after market and bought from ebay and we dont have a spare fob, we took out the black box to start it but obviously an unlockable jeep which can be started with a screw driver is a pain.

i plan to

buy a new black box for the central locking.

i want to mount a switch on the dash to act as the ignition being on and the one i want is rated at 36amps

then a push start button,

any tips, comments, or advice as to wether this will work would be very much appreciated

thanks
Answers:
parts store not hardware ! lock smith ! a smith can mak a key to match your lock. i'd get a metal detector .
In theory it will work, our race car has exactly that, but there are two problems.
1 The ignition lock operates the steering lock. You will have to disable the steering lock in a way that it CANNOT accidently relock, or only drive in circles.
2 There is also the accessory position on the ignition lock, this would need switching too. You could route it through the main ignition switch, but this would mean stuff like the radio would only work with the ignition on. Otherwise you'd need a second switch.

Is a new lock set SO expensive to overcome the above problems?
It's also possible that a dealer may have your key details on his computer database. Has the previous owner got a spare set or the key number in a diary etc? Have you checked the vehicle details, if you still have the owners manual, sometimes they are written there, all our vans come with a slip of paper in the vehicle papers with the key number printed on it.
Hope you get some inspiration.