Remember though that is a petrol V6 lump. No turbo, no fancy DPF or otherwise. Straightforward tried and tested solid petrol engine. They do tend to get up to operating efficiency pretty quick from what I recall of mine. Although agreed, this does seem excessively low miles. I'd like to find out why - as there may be a perfectly reasonable explanation (second car in house? used by elderly relative? bought but found to be too expensive to run?) ...
You do not mention the one thing likely to fail first - the catalytic converter. These must get up to operating temperature, if not they corrode from the inside out and simply fail. That means noise and/or failing the emissions test.