if you follow BW you can see any post she liked of Alice, it starts in november 2018 (that's when she probably became an extra on Harrow) and stops in may 2019 (during that time Alice was visiting Ioan in London btw)
Ioan was in 2019 in Oz until early march, but she continued liking Alice's pics till may. to make this theory work she and Ioan would need to already be in contact
If we want to construct a theory out of the liking angle I think till may 2019 she was just proud to be on the same show as a international star and a bit of a fan of his, thus also following his wife, all very innocent. Then her marriage started breaking down and she felt bad for liking pictures of the wife of somebody she has a crush on, now that she is about to become single. I definitely dont think that the affair was there yet (neither does Alice fwiw)