DOC cover - drive other car (policy excludes partner's car)

[rallycross]

Question re DOC cover and excluding partners.
Is this a normal exclusion on DOC?
Which insurers offer DOC and do not exclude driving partners cars.

My wife's fully comp' and her policy states she has 3rd party DOC provided the other car is insured.

She sometimes drives my cars on this basis.

She just renewed her fully comp' and went with E-sure.
The online policy said it provides DOC.
But when the certificate arrived in the post it states DOC 3rd party but exluding partners car.

Anyone recommend an insurer who's DOC does not exclude partner car.

[Crusoe]

Add each other as named drivers on the other policies and it will probably decrease both at renewal.

[MrBig]

Fairly standard clause in my experience.

[jon-]

Esure... shock.