Here's a quote from the website of a leading law firm, I won't mention the name and will confess an interest that a friend of mine works for them, so I pay her for advise in Bacardi and Coke (other brands of white rum and cola based currency are available);
"where support is provided by family members it is possible to arrange a gratuitous care payment in certain circumstances. This would be relevant where the family member does not intend to enter into an employed role but provides a large degree of support to the client. The are treated as being exempt for tax and national insurances purposes provided an application is made to the HMRC for approval. We can support you with this process and have already supported numerous clients in this regard with great success"
Make of it what you will, I posted link to case law earlier and the importance of the phrase "gratuitous care payments" as being the correct description not a "wage" or similar wording although it amounts to the same thing.
I'll invest some more Bacardi pounds and see if I can find out what exactly the "it is possible to arrange a gratuitous care payment in certain circumstances" bit means,, is certain circumstance just a way of saying we won't tell you anymore without getting some money out of you, who knows, I'll risk a hangover to find out.
K