Thanks Roo, that makes things much clearer now. Do you think "PWR" is suitable when towing, or is it just for around town?
Another question; if I am towing up a hill and I manually drop back a gear (or two), the engine revs go up (of course), however I get more power to get up the hill. Is that something I should do or should I just leave the gear in "D", go up the hill slowly, and let the gearbox work it out? Is the increase in engine revs detrimental, meaning extra stress on the engine, gearbox, heat etc?