[Orwell1984]

http://www.archieraf.co.uk/archie/28_29april1942.html

The above details the April 28/29th 1942 Tirpitz Raid with the ability to drill down to specific aircraft histories.

On doing so the following was found:
http://www.archieraf.co.uk/archie/54...april285487ofv

On 28th April 1942, the crew of Lancaster R5487 OF-V from 97 Squadron took off at 2100 hrs from RAF Lossiemouth on the North East coast of Scotland to participate in an attack on the German Battleship Tirpitz which was moored at the time in Fættenfjord in Norway. Weather was good with clear visibility. Attacked estimated position of primary target from 8,000 feet, Tirpitz was not visible. Bombs were also released on flak positions and on Værnes aerodrome. The flak experienced was heavier and more accurate than on the previous night. The aircraft and crew returned safely to RAF Lossiemouth landing at 0440 hrs on 29th April 1942.

Note highlighting. This was the only aircraft in which I found specific reference to an attack on Vaernes airfield.
Hopefully the time frame fits with what you are looking for.