AirAsia X (D7) announced its first route - KUL-OOL, four-weekly - last Friday. A promotional ticket for KUL-OOL-KUL was about £92 all-in.
D7 has permission to begin flights to/from STN. But whether that'll be its first UK destination is completely uncertain.
D7 will be acquiring 340s - two, I believe. I wonder whether these would be used to/from the UK, or whether it'd operate the 330 via BAH, as some info. has suggested.
The biggest problem is the almost complete lack of information. I think it's just a case of waiting to see what materalises.