Followup on professional negligence

Sir, in Hedley Byrne & Co Ltd v Heller & Partners Ltd (1964) The claimants (Hedley Byrne) asked the respondents, who were Easipower’s bankers, for a reference as to  the creditworthiness of Easipower.  In the 
absence of the disclaimer, the circumstances would have given rise to a duty of care because defendant knew that claimant would rely on their statement. CORRECT?

In Jeb Fasteners Ltd v Marks, Bloom & Co (1982) The defendant accountants audited the accounts of X Co. The audit 
report was negligently prepared. The claimant then took over X Co.
Here again the defendants owed the claimants a duty of care because they 
knew the claimant company was considering taking over X Co and 
thus were likely to rely on the audited accounts. CORRECT?
I know thats a different matter that the claimant’s action for damages failed because they had taken over the company to 
obtain the services of X Co’s two directors and not on the basis of the accounts.

In Morgan Crucible v Hill Samuel Bank (1991), the defendants knew MC would rely on the circulars for the particular purpose of deciding whether or not to make an increased  bid and intended that they should. So again defendants owed the claimants a duty of care. CORRECT?

However, in Caparo Industries Plc v Dickman and Others (1990) and James McNaughton Paper Group v Hicks Anderson (1991) decision of court was different from the above 3 cases. Here duty of care was not owed. Can you please tel me the reason of this?