Apologies for a stupidly long post, mods please be kind.

I have been researching my grandfathers past as he was a POW in WW2. He survived the camps and returned home and died in 1981, about 5 years before I was born. But ive always been curious about this guy i never met after hearing about him from my parents. I know my Mum's knowledge of her Dad's war time and POW past was limited as he didnt speak about it. Cant blame the guy. All they knew was that he served in India for a couple of years, then was a POW for over 3 years and they thought that he was in Burma. My grandfathers name was William Gray. He was Scottish and served in the Argyll and Sutherland Highlanders, 2nd Battalion as a Lance Corporal.

From my research (which i have been helped with a lot and will give credit later) I have been able to establish the following:

He was taken prisoner in an area called Titi near Kuala Lumpur, Malaysia on 4th Feb 1942. Transferred to Changi Prison in Singapore on 17th July 1942. Then after nearly 4 months there he was transported in letter party M / Train 12 on 5th November 1942, to a place or places I dont know where. Then there is a big gap until the end of the war. When the Japanese surrendered (August 1945?) we know he was in a place called Ubon in eastern Thailand which isnt far from the Laos and Cambodian borders. There is an airstrip there which many POWs built so he may have worked there alongside others in building that.

Most of the above information came from my visit to the Thailand-Burma Railway Centre (i think it was also called the Death Museum) in Kanchanaburi, Thailand a few years back. I went to south east asia to travel and just took his army number with me and the guy who worked there (Andrew from Australia, credit where its due) was such a great help and gave me all the above info. Like i said, before this my parents thought he was in Burma the whole time so this guy gave us lots of great information which no one in my family had any idea about.

Since then, following Andrews instructions, I have also found my grandfathers Japanese Index card through the UK national archives online. I have previously posted this in the r/translator subreddit and some kind folks helped me to translate the japanese writing into english. It basically confirmed what we had already known, but also gave us a couple more details.

On the back of the index card it said " November 1942 transferred to Thai POW camp Branch 1" (or 1st branch)

Then there is a gap and it says " 1945 August 30th. At Bangkok, returned to Allied forces "

So there is a gap of about 2 years and 9 months which I havent been able to find out anything regarding his whereabouts. It could be he spent all that time in Ubon but I am curious to know more, as my understanding is that lots of the POWs where moved about to different places as and when required. I dont know if the mention of being transferred to Thai POW camp branch one (or first branch) is information that could lead to where he was sent, or if this is a false lead.

I have requested a page check in the national archives in a war office box containing information on WW2 POWs which lists details of the men named Gray - Grieves. The war office box catalogue reference number is WO 344/379/1. I am hoping that they have more info and what I am looking for is to see if they have his Liberations Questionnaire, if he filled one out that is. Apparently once returned to the Allied forces they tried to get all the POWs to fill these questionnaires out to detail their movements and the things they had done. But not all of the men filled it out. So it may not even exist, but its worth a shot.

I found one other thing, which is a list of POWs i found on the national archives as well, i cant remember which WO box it was in but i saved the image. It is a list with different headings along the top. I will give the details below concerning my grandfather from this list:

Name - Gray, William

Ser - A

Rank - L/Cpl

Card No. New - 1 7535 (the list show the 1 as roman numeral then the 7535 as normal)

Card No. Old - 1 18609 ( as above, the list shows the 1 as the roman numeral, then the 18609 as numbers)

Former Camp - M 7195

Regtl. Number - 2878685

Remarks - M-18/3/17

Thats all the info i have relating to old Willie. The things im most curious about from this list are the Former Camp number M 7195, alongside the old and new card numbers and the Remarks section. The remarks sections looks like a date but he was born on 28th march 1915 so i dont know what it could be relevant to if it is a date, since he would just be coming up on his 2nd birthday at that point. I dont know at all what the card numbers new or old refer to.

Can anyone help me to find out more information about him? Or a suggestion of where to look or request information?

Specifically what i want to find out is where he went to after leaving Changi and before the wars end when he was in Ubon. I know the date he left Changi and what train he was on (Letter Party M Train 12). From the japanese index card it says in november 1942 he was transferred to Thai POW camp Branch 1" (or 1st branch) From this random list ive found it gave me this former camp number M 7195. But i cant find any information about where this train would have taken him to, or where this Former Camp was.

Maybe I am not good at researching or maybe I am misunderstanding something, or several things.

Applogies for the long post. Any help or suggestions to further my search to fill in this gap would be greatly appreciated