My 1985 LR 90 has 6 keys. I was looking at reducing this.

1 for ignition, that's always going to be the same one
1 for bonnet
1 for RH door
1 for LH door
1 for rear door
and 1 for the lock on fuel cap.

Now I don't mind the bonnet one or the fuel one, I don't fill up often enough for it to worry me, besides, the key for that padlock fits 2 padlocks and I keep the other in the centre console to secure a trailer if I park up. Be nice if I swapped all the doors for 1 single barrel lock.
Before I delve into this, anyone done this lately?

For the doors you can buy barrels all keyed the same & exchange them for what you have.
You may be able to do same for ignition depending on model, type of ignition key.

You can certainly get new barrels for the doors, all using the 1 key, but the ignition and petrol cap are different.
Dunno about the bonnet.

The ignition key is different from the others, but you can swap out the 3 door barrels. Only the early trucks had a bonnet lock like yours, later ones have internal release handle. Find how to change on the Youtube.