We are flying with Avianca in Ecuador in December and I tried to book our seats on the flights, however the system would not accept UK postal codes on the final payment page, repeatedly I received an "invalid zip code" message. I called Avianca to make payment and was on the line for 51 minutes. I do not fly with Avianca very often but if anyone from Avianca reads this please note the issue of making a payment with a UK credit card...