Who is right? Lloyds or Nationwide?

Lloyds tell me that no Clerical andMedical policies are ppi related.

That is correct. Clerical Medical is a life assurance company. It is not a general insurance company.

The Nationwide Bank list on their ppi claim form a policy sold by Cheshire Bdg Socy a policy named as Disability protection plan. .... sounds the same to me...

Lots of products have similar names but cover totally different things. There is often an overlap with income protection and payment protection and some critical illness or hybrid plans.

Lloyds say the policy I had wasn't ppi as it wasn't protecting my payments. It was simply a policy to pay me money if I became ill for any length of time.

As PPi didnt exist in 1972 but income protection did, then Lloyds are correct. PPI is short term insurance issued by a general insurance company. The policy you had is a long term insurance issued by a life assurance company. It is not PPI.

So, next steps?

Making a PPI complaining about a product that is not PPI and is about 10-15 years before PPI became available is non-starter.