Correct it’s the only direct. Other solutions involve going from Bogota through the US with all the hassle that entails or via Madrid (Avianca, Iberia, Air Europa), Amsterdam (KLM) or Paris (Air FranceJ. The Avianca direct is a good solution, in particular if you are a fan of T2 at Heathrow late at night...
All the changes so far have been on the domestic leg from MDE to BOG. If you live here you learn to plan long layovers in Bogota for safety. I live near the Medellin airport (JMC Rio Negro airport) and there are thunderstorms most nights. It isn’t unusual to have long delays making connections difficult or even cancellations.
The financial press here today (la Republic) is running an article that ticket prices for the holiday season are up 15% from last year and that as an example LATAM have gone from 82% load to 95%.
Avianca also seem to be having to pull (some?) of the 787s for ‘special maintenance’ and replacing them with A321s. Presumably they’re not planning that for the 787 dedicated LHR route otherwise it’s going to be a long glide from around the Azores to Heathrow...