Objectively speaking, Vietnamese is much easier to learn for an English speaker too since they also use the Latin alphabet.
Not sure how many Vietnamese speakers are in the UK though.
I dunno about “much” easier, as all tonal languages are pretty rough for English speakers and many of the phonemes are totally new. Easier to learn to read and write for sure, but listening and speaking are a different beast.
True, but I was comparing it to Mandarin and Cantonese (OP didn’t say which Chinese language but I assume it’s one of these). Both of them are also tonal languages from what I understand so in that way they are all different from English.
However, Vietnamese is easier since the characters are more recognizable. Listening to movies/shows with subtitles makes it easier to understand and it’s easier to pick up reading Vietnamese than reading Chinese.
The issue here though, is that for OP it seems like Chinese is the more practical language to learn since their “friends” also speak it.