As Carnage Matey has correctly pointed out, 'Grandfather rights' is merely a way of saying that when a company is taken over by another company the the pilots who are Captains on that particular type have the right to remain Captains, irrespective of their seniority position within the new company, as long as they remain on that aircraft type.
Any internal move between fleets will mean that the pilot takes up his natural position with respect to the seniority list, in other words a move to the right hand seat.
What it allows is that the pilot can choose to take a fleet move, a move that would have meant leaving the old company and rejoining the new at the bottom, if he wishes or, as would have originally been the case, remain on the fleet as a Captain.
These magical Embraers seem to be as elusive as the Gatwick A330 beach fleet.
Lcy-Nyc, won't be Citi Flyer. Probably won't be LHR, more than likely Gatwick on cheaper contracts and used to multi mode operandi.
HZ123, can't agree more with the time off for ramp ops at LHR, but don't beat the drum with those of us who have been regularly turning in 12.5 hour days at the controls of an aircraft.