Hello Julie and welcome to the forum.
The information in our PoW database regarding James Smith has all come from the ICRC files. He has two index cards, one of which, I am guessing you have missed. His service number, if he enlisted into a regular battalion, suggests an enlistment date between February 1912 and March 1913.
He was transferred from Libau to the hospital in Stettin suffering from frostbite. Libau is now Liepaja in Latvia. 1000 British PoWs were sent from Döberitz to Libau in May 1916 in retaliation for German PoWs being returned to France to work on the docks. The British PoWs were employed unloading ships in the Libau docks. The conditions they were kept in, and the weather, were particularly harsh.
Thomas Dodd would appear, due to his number, to have served with the 20th Bn. His date of entry into theatre (10.11.1915) ties in with the battalions arrival in Boulogne on the 9th November. He was transferred to class Z reserve on 11.06.1919