Dell Mobile Projector M115HD

I purchased this mobile projector May 2014 and have only used it about a dozen times.  It had an occasional problem in that a line appeared across the centre of the projector image.  It is now doing it every time.  It is Ok when first switched on but appears after about 5 mins.

It is a fuzzy line which is constantly moving, presumably the signal is not being projected correctly for a few lines across the screen.

The line is wider than the screen.  I have tried it on another computer and the line still appears even when no devices are plugged in.  So it must be the projector.

I have photographs but there does ot seem to be a way to upload them.

Any help/advice would be appreciated.  Is just throw £350 worth equipment away and not buy Dell again?