Hey guys should there be a relay in this spot only thing thats not working is central locking i carnt find the blue c/l modual ive only got key no fob and whats this silver box theres no part number on it but have dare unplug it yet 😝 any help would be great thanks Any

 

that silver box is an aftermarket addition.
would have to trace the wires to see where it is spliced into to work out what it does.

my guess is it is something similar to what i have done and is an aftermarket remote kit wired into the door lock and unlock wires to give keyless entry using an aftermarket remote to get around the factory system not working

 

Your empty relay position is for "Accessory". It is not for central locking. I've never used it. I don't recall if it even has wires attached under it. But it could be used for an aftermarket device, maybe like the mysterious cigarette case in your fuse box.

The left relay is for the heated rear window, a yellow base. The central black relay should be for the trunk release. Then the next two with green and red bases are for fuel pump (go) and high mounted stop lamp (stop). The relay in the fuse box is "ignition on" and sends power to whichever items are connected through fuses 10, 12, 14 and 16. Cool, huh.