Have you used the proper DIN connectors ?
I have no idea why the central locking wouldnt work.
If you have snipped and joined the connectors - you have def gone very wrong somewhere along the line. If the battery is draining too - it looks like the stereo is staying on and not turning off. The main wires to get right are the perm live and the only live when ignition is on- this powers the unit and the perm live keeps the stations and presets etc but shouldn't drain the battery.
If you have used the DIN connectors and it didn't do this before - you need an auto electrician to diagnose where its gone wrong.