The link above to the legal expert was very interesting, his view that TULRCA 1992 does not protect strikers from any detriment arising directly from actual industrial action, other than from actual dismissal in the protected period, would, if correct, scupper any claim by UNITE that BA were wrong to withdraw staff travel. (Sadly IMO, but I know I'm in a minority on that point here, I just don't like the idea of punishment for a legal strike)
Also, the past case quoted in the European Court, where the court agreed article 14 (prohibition of discrimination) was breached, but decided it was 'justifed and not disproportionate' would seem to make a European Human Rights ruling in UNITE's favour unlikely as well. The fact that BA have offered to give back Staff Travel in full by 2013 will make the original withdrawal seem 'not disproportionate' I should think, especially as an earlier -rejected - offer included seniority on commuter routes immediately (don't know if the latest offer does).
If UNITE's lawyers have reached the same conclusion (which would explain why they are prepared to 'recommend' an offer than precludes them from taking further court action) hopefully a sensibly worded ballot will be issued after the 'imposition' ruling tomorrow. No point trying to second guess that one, we'll hear soon enough.