Why the "Hallibag"? Just curious.
The Lancaster would have been a far more suitable airframe for this purpose.
I'm assuming that you're trying to "re-purpose" obsolescent airframes towards the end of the war?
Not certain that this would be a net gain for the RAF at this point, the airborne radar units then in Naval Use were rather primitive after all.
In the post-war world there were thousands of surplus Lancasters available so hanging on to a few dozen Halifaxes (and maintaining a supply chain for them) makes no sense whatsoever.
The Halifax (while far better than the Stirling) was an utter failure (altitude/range/payload), when held against the Lanc.; an "also-ran" at best, and a nightmare for the supply chain in some regards.
This is one of the reasons why Canada set up Victory Aircraft to build Packard powered Lanc's under license for 6 Group; the Air Ministry seemed to think that "fobbing off" the Halifax production to the "colonials" was a "fair" thing to do. The Halifax was suitable as a gap filler, while the production of Lancaster's was ramped up towards the Spring of 1944. God knows it was better than trundling over Germany at 15,000 ft in a loaded Stirling.