[paulmcmillan]

Naval Operations of the Campaign in Norway, April-June 1940 By David Brown
On Google Books
Operations April 8th 1940

"He also sent off his second flying boat to search at that time and the Rodney's aircraft at 1843, (5)
but neither gave him further news of the enemy. ..."

5) "The Commander-in-Chief was by this time so certain that the Germans were about to invade Norway that he personally told the pilot of
this Walrus that he was to allow himself enough fuel to land in Norwegian waters and then give himself up ; that he would be free next day
since Germany was going to war with Norway, when he was to get hold of enough fuel to take him back to the Shetlands. All of this he did"

So it looks like it was Rodneys Walrus