Lambda sensor removal

I'm about to drop the downpipe and need to disconnect the lambda sensor and I'm having difficulty following the wire, from a photo it appears the connector is at the end of the head. To access this do I need to remove the engine cover or is it possible to do it from the boot access, if so what do I remove here, airbox?. The cable is also attached to the engine near the downpipe is this a clip? or do I have to unbolt it (it's pretty dark down there0, is this the only clip?

I intend when I locate the connector on the head to attach a string to it so when I disconnect it and pull it through I can pull it back again following the same route. Will I have problems doing this ie will it get caught on anything or is this bit simple.

When i changed mine i had the back wheels up on ramps and un screwed it with the manifold still attached. Engine lid was removed to let more light in and easier to reach the multi connector. If you put your hands down above the gearbox, move the cable out of the for the temp gauge and reversing light switch, the only other in that area will be the lamda cable with a multi block connector with 4 wires.
Good luck

Thanks Steve, its done now defo engine cover off but what a pain just to unclip a plug!! at least I now know why on the rare occasions the hood is up it rattled, two of the clips weren't done up. Now all the hood is in this state I suppose when it's time to put it all together I will have to replace the window panel with the HRW one I bought ages ago.
The exhaust parts should arrive Mon/Tue so the car should be back together on ?????????????????