The Return of the Comet (in 2002)

I was thrilled to read in Airliner World this month that my favourite aircraft is to return to the skies in 2002 to celebrate the 50th anniversary of the first scheduled passenger jet flight from Heathrow to Johannesburg.
What puzzles me, however, is the registration which has been requested for the Comet 4. Why have it as close as possible to the aircraft which made the first Trans-Atlantic passenger jet flight? Why not go for a registration close to the one carried by the first Comet into passenger service (G-ALYP), if this is what the flight is supposed to commemorate? Is it because there is another aircraft in service with G-ALYP registration, or is it because the G-ALYP Comet crashed?