She has indeed included that but I don't recall that she stated it as a proven fact -I'm certain she wouldn't have been that expansive- I think it was along the lines of it having been rumoured. It wasn't explored, which makes me think she put as much credence on it as I.
To me, Jane, It doesn't matter WHO has said it and whether they are a supporter or a guilter, I don't believe it and that's for many reasons. What the heck was Sheila doing with the drugs, baking?? I've never heard of a dealer who would let someones debt get that high. I don't believe Sheila has a 40 k drug debt, I wouldn't believe Jeremy had a 40 k drug debt and I wouldn't believe Jeremy AND Sheila between them could have a 40k drug debt, no way.
I am sure it was one of the MANY silly things, like village gossip, that went around at the time - a bit like Chinese whispers. CAL mentioning it as rumoured makes sense because that's all it ever was.