Thanks for the comments guys.
I'm still a bit perplexed. There are a few different numbers stamped here and there.
The engine number is definitely 231045.
Then above the engine number is stamped "51"
However, there are few more numbers stamped. 24754 - 1600 (I would assume its a 1600cc motor).
Also stamped is 799.
I know its a bit confusing, but any help would be appreciated.
Thanks again,
Kevin