So I had a look under the car last night and found that the cross member, right in the middle section, is wet (oil). I also found the back of the sump is damp with oil, but the gearbox underside appears to be dry. The wet patch appears to be forward of the steering rack.

I'm just looking for suggestions on what it might be (which leads to how much it's going to cost me $$).

Am I correct in almost ruling out the rear main seal?

Pics attached.

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