Thanks for all the replies. But, er, you're all wrong
I finally got a reply from the revenue, and the way it works is this:
- Between husband and wife, the split has to be 50:50 or based on percentage owned, so if I had 99% and my wife had 1%, 99% of the income would go to me and I'd be taxed on it.
- Between anyone else, you can do it how you want. So if I own 99% and my mother owns 1%, she can still receive 100% of the income and pay tax on it.
So in my case, my wife and I will own 49/50% each, and my mother will own 1%. All of the income will go to my mother, she'll pay the tax. The tax burden for my wife and I will be 50% of nothing, no tax to pay. And the IHT/CGT issues are negligible.
Definitely one to bear in mind!