As a reminder of what I know to be a 'fact', and not a 'rumour', when Bristow was awarded the BP work in Humberside, previously held by CHC, the lawyers all agreed that it was a TUPE transfer. Those who didn't move elsewhere within CHC moved across to Bristow. I think both companies used different S76 variants.
It's a complex area in which to interpret the law, so probably a good money-spinner for the law profession.