Also remember to factor in any cabin bonuses depending on your mileage program and oneworld status. As a BA Gold/Silver, those status + cabin bonuses by flying BA do rack up the avios points (though probably not £350 worth). If all things are equal, including the price, then I would choose CX. But if CX is slightly more expensive, then I would personally look at flight timings/connections/arrival/departure times and go with what suits you best.