Hi thanks for the reports … the BIG transition is a tailored record-set and not included in our source due the complexity of coding. The fact, that this transition isn´t working well now, we will remove this transition with the next upcoming revisions, latest with the AIRAC 2014. Sorry, but this is not handle able and must flown by hand in the future.
Thanks for your understanding
Richard
PS: there was also a posting about this issue with a good real-world information about the BIG transition and that the coding is too complex - look here Bnn1B Star EGLL (27L & 27R)