And no, sorry ifitiaint but the topic of insurers came up in conversation and I wasn't told the name of the company.
So, you can't substantiate your claim that an insurer has actually refused insurance cover on this basis.
But I certainly know that clubs are refusing to rent aircraft to pilots without at least an NPPL medical declaration or a Part-MED medical.
Aren't you merely confirming that clubs are acting on advice which you have issued? This doesn't really confirm anything other than the confusion which has been introduced due to lack of clarity in CAA-issued documentation.
ifitiaint...