"We are going back to London next year."
As i understand it, they are interchangeable semantically, but they are usually used in different contexts. I.e. people will understand what you mean, but it will seem like a strange turn of phrase.
My understanding is that 会 - as far as we've learned to use up to this point, it means to be able to/can do something. Native speakers please correct me for other uses that might make more sense here.
So your sentence could be read as, "We will be able to go back/we can go back to London next year". 我们明年会回伦敦.
Which has a slight different meaning compared to "We are going back to London next year." 我们明年回伦敦
why is 到 not used here for "to"? is that contained in the verb? would you not use that hanzi in a location/motion context?
From my experience, you only use 到 when talking about a non native country, bc you wouldn't use 到 for 回国