Looking for information for John Dickson Laurie

Hello,
My name is Sean Trott and I am trying to find out information on a person who is buried in our Services section of our cemetery in Hawera, New Zealand.
His family had been given a brief history of his service and it appears he was awarded a DSO.
There is reference to him serving with many branches during WWII and also after with the US Navy Seals up to the Korean War
Here is what the family have given me:
John Dickson Laurie
Service Number 44757
Merchant Navy 1938, 1939, 1940
Royal Navy 1940
Gunnery School Whale Island Promoted to Lieutenant
Trained as Frogman HMS Dolphin
Special Boat Service of either 47 or 42 Royal Marine Commandos , CO of 4 Company, 1942-45
Team Leader for Operations for D-Day landings on Sword Beach for Operation Overlord for which was awarded DSO (Award is in Chapel at TS Dolphin)
Captain of LST after Operations
Was transferred back to Merchant Navy then asked to help train US Navy Seals and awarded US Navy Cross
We are wanting to know if this is fact as this is going to be part of a display in our Club.
I have asked 42 Commando Association about his service and it appears he does not appear on their lists. They have said to ask the Royal Navy for his records but it can only be done by family and I am asking if there is any way I can get this information as I think there maybe a little discrepancy of his service and do not want the family to be hurt if there is.
Any help would be grateful.

Hi Sean,

The probability is that he was in 47 RM Cdo if he took part in the D-Day Landings as, at that time, 42 RM Cdo were serving as part of 3 Cdo Brigade out in India/Burma.

Nick