I've always feared that! Luckily I have 2 sets of keys now just in case. I hope you find yours....
There is a usually code on a piece of paper on the inside of the strap that holds the ignition lock on. You'll not get a key cut from that but at least you might find a replacement at an auto jumble. Failing that the ignition lock can be swapped without needing a key. I don't think the ignition barrels are replaceable.
The door lock barrels and the boot lock on the saloon are the same as Landrover ones, not sure which series, but you'll probably need a key to get the old barrels out unless you're good at picking locks. They're not that hard to pick if you can do it. Once you get them out there is a number stamped on the side of the barrels if I remember correctly.
You may well find that the driver's door and boot locks are so worn that quite a few keys will open them.