It looks like it might have been done by looking at the progression of your natal Sun, either by solar-arc or secondary method. Progressed Sun looks to cross the cusp of your 2nd house, the house of your income and possessions among other things, when you are 41. I've not looked at the progressed charts to see what else astrologer may have seen, but perhaps there might have been Saturn in the picture, representing loss.
Anyway, that is my best guess. So it may be accurate, but one would have to construct and study all the relevant charts to see if they agreed. It seems like a rather specific interpretation. But that, I mean, it seems it would have been more accurate to say you may lose income, rather than you will.
Thank you for your reply! Very kind of you. I will have a look at progressed charts..still in very early stages of learning about it all this forum is great of although I am finding it fascinating its still a bit like learning chinese! haha! It poses the question though how much is fated/lessons and how much is about free will/effort. I suppose that's why you said you may lose...Interesting. Thanks again xx