Conflicting dates of death as a pow

[Daisykitkat]

Hello
I have a Donald Lamb born 20th September 1913 Belfast service number 815566
Served in the 3rd battalion Royal artillery but during the war records show he was part of the 6th heavy anti aircraft regiment.
Family tales tell  he was beheaded .
On the common wealth site it gives date of death as 5th march 1943 yet other documents show on or around 4th April 1942 .where would I look for confirmation of death year
Any help much appreciated

[ShaunJ]

There are reasons for the confusion. See https://www.roll-of-honour.org.uk/l/html/lamb-donald.htm

[Daisykitkat]

Thankyou for taking the time to reply I was going by this