The information helped the allies win the battle and saw Captain Oldfield awarded the Italy Star medal.
Daughter Fiona Oldfield said: "In our youth, it was more 'oh no, dad is telling his army stories again', but as we grew older and realised the significance of his service and what he did, then yes, I think the family is very proud of him.
"Particularly, that he has remained so interested in his history during the Second World War over the years."
Despite leaving the service in 1946, the unit will always consider him one of its own.
Colonel Phaedra McClean, Corps Colonel Reserves, Intelligence Corps commented: "It is a fantastic opportunity - we do not get the chance to speak to individuals like Jack about their service, about what they did.
"To be here and be part of it is super, and to retain the links to the Corps, I think for him is also quite special now."
On Captain Oldfield's 105th birthday, a message was read out from the Queen:
"What a splendid achievement. I send you my warm congratulations and best wishes on your 105th birthday."
Captain Oldfield says he doesn’t have any secrets to share on having such a long and healthy life.
He is sure there is still plenty of life in him yet, and is already planning his celebrations for his 106th birthday.