I'd be tempted to leave it in the outgoing boat , seal it back in and wave good by to the channels.
You'd have to have it reprogrammed anyway with the new boats MMSI anyhow ....
Buy a new one, programme the new MMSi number to it ( when you get it registered to the boat via the ofcom site and see about getting the channels put back in to a new one.
On the basis you are keeping the new boat for a while I think it would serve you well. The the cracked one will give up at some point with water ingress,
..and youd have to buy a new one anyway . Its probably not a big cost as a % of the overall cost of a new boat . And sale season is very nearly here ( and boat show type deals ? )