I got a similar call to Peter from 18 July 2013. Someone claiming to be from Members Alliance, and asking same sort of details. I figured it for either a scam or telemarketing and fobbed them off.

Caller claims to be from Members Alliance offering a way to save thousands as long as you pay tax and have over $110k equity in your home. When I said I would look at their website and if interested I would contact them on the contact numbers listed I was told I wouldn't find this particular offer as it was only being offered to specific households. Caller got his back up when I said that I googled Members Alliance scams.