Not sure, I found these:
Victor Sassoon - Wikipedia, the free encyclopedia Legend of the Sassoons
I only ever saw one 3 litre in Indore. I don't have any details, it had an awful dynamo belt drive arrangement, a huge pulley driven off the back of the camshaft.
It would be interesting if those with access to the remaining W O Bentleys in India could come up with some numbers and details.
Can anyone help?