Immigrationboards.com

The news section of UKBA's website has the following piece.

http://www.ukba.homeoffice.gov.uk/sitec ... egulations

I find the following view rather interesting

Rights to reside in the UK on the basis of ECJ judgments do not stem directly from Directive 2004/38/EC, therefore they are referred to as 'derivative rights'. This means that the recognition of this right by the UK is not equal to rights under the directive.

This mainly refers to non EEA parents of EEA national child (Chen cases). The HO view is that the right to reside is temporary (i.e. as long as the child is minor) and that it doesn't lead to PR under the directive. I would guess they will have a similar view for Zambrano cases.