I did a quick search on the Internet for 7.92 Brens and found this:

"As a bit more info, the Red Chinese had quite a large quantity of 7.92mm Bren Guns made by Inglis in Canadaicon. (That's 7.92mm Germanicon not 7.62mm NATO). They were mainly captured from the Nationalist Chinese. A lot of their soldiers also used 7.92mm Mauser rifles..."

Bren Mark I Light Machine Gun, Bren Mark III, Bren Mark IV

As well I found a reference to OT serial numbers for Chinese Brens at Bren guns

"The Inglis 7.92mm Chinese contract Brens carried the 0T as well as the CH serial number prefix..."

Sounds like you've got a Chinese Inglis made Bren.