I guess the pronunciation will depend if calling BA or IB.

Avios seems to be a rather illogical name choice for a British/Spanish FFP.
Quite different sounding in both languages.
From the "a" to the "v" vs "b" to the final "s".

If it were a British/Japanese they would have thrown a few L's in there just for the fun of it.
And a British/French would have ended with a couple of "R's" and "I" and "E" to confuse.

GBM