Hi. Have been trying in vain to locate 

alarm on car. Have tried inside/offside wheel arch, etc.

Have been having problems with alarm system. 

Many thanks.

Have a look under the rear seats, looking for a cable that goes through the floor on the left, (UK passenger) side.

If you find one, I think you'll find the alarm horn underneath the car below there.

Hi. Thanks for the reply, also apologies for the late answer. 

Lifted rear bench seat and took photo. Please see attached. It looks like the big round plastic cover is for the fuel tank, which sits below it. Not sure about the two outer lines. They look like two tubes rather than wiring. 

Hopefully you can have an idea by looking at the photo.

Kind regards. 

Hi.

Look on the left side under the carpet at the front of where the seat would be. Petrol tank cover is on the right side of the car. Outer, rear wiring is to ABS sensors.

Look under carpet over here (red marking):

 

Don't bother, I think it's somewhere else.

I can't understand what these instructions mean, or where the image is, but this is what workshop manual says:

 

That image shows the scuttle area tucked underneath the windscreen where the ECU is on many of our vehicles, you can see the windscreen wiper spindle, the bellcrank and linkage arm on the right.