No serious contender will want to be involved until the Cold Hand of Branson has a few fingers severed and he loses the majority stakeholder position. That alone has ensured the Singaporean stake remained unsaleable.
Any kind of flotation or restructuring of Virgin Atlantic will need the existing shareholders to be reduced or eliminated, with a nod to the EU rules. For that alone it'll be a tough deal to try and call. Many potential bidders won't fancy Sir Beard being involved in their companies either which means share swaps may not be the ideal solution.
BTW the two A333 with no Upper are for MAN and LGW Orlando services that traditionally haven't sold well in the front cabin, as they are packed out with Virgin Holidays punters off to see the mouse.