I'm not sure how the Seniority list works at Virgin, however one thing to consider is the long term.
Yes, sitting at VARA for 7+ years while new hires go onto the Jets might be a hard pill to swallow... but down the line, once you've finally escaped the Turbo-Props and secured a Jet Job, wouldn't an extra 7 years Seniority ensure a Widebody command that much quicker?
Just an outside observation. The reason Air NZ Link lose so many Pilots externally is because their seniority lists are entirely separate from the Jet Fleets so Pilots lose nothing by leaving. Would be a very different story if we had a group seniority list.