I have 18,000 miles in my BA Avios account and I would like to put them to the best possible use in upgrades. I am flying Aer Lingus in 2018 BOS-DUB. Can I use them to get upgraded to business class? If not what do you wonderful helpful experts suggest I do with them. I am also planning a trip to the Cook Islands. Any possibilities there? Cheers! Mick Mc Grenaghan