Airportable

Let me clarify the position you now find yourself in. As you have said you are waiting for your replacement lock mechanism to arrive & in the interim you have disconnected both poles of the battery, connecting the cables together to drain any voltage held residualy in the various MEMs modules. You hope this action will reset the ECU. Having then reconnected the battery you don't have any visible indication of power. You say you have checked the big fuse, which is Ok, which fuse is this, the one under the bonnet (which is the EPAS supply) or the fuse behind the engine/boot bulkhead. To know where you're up to will help those who wish to guide you back to the high road consider what advice to proffer. And finally can I say there's value in the comments Steve has made.