Looking for advice just joined

Hi, just joined and looking for advice. I have a 2003 Freelander 1.8 petrol. First item I seem to have an intermittent problem than when I select reverse, the HDC amber light comes on, and the rear and front wipers work together, however when I select a normal gear and move forward, the reverse lights stay on constantly even though I am not in reverse and the HDC lights stays on. As I said it's not all the time. Second issue is I was told if I remove the prop shaft and convert to 2 wheel drive. I will get much better MPG. Has anyone done this conversion? It looks simple to remove the propshaft from the idr and blank it off. Thanks for any help received.