Washing powder marks left on clothes

[Tertius]

What am I doing wrong???

Its horrible when that happens.
Could be a couple of things:
My best guess would be that you overloading machine with too much washing at once, so it cannot be rinsed out enough. The washing has to tumble around to clean properly. (done this before, when I tried to cram in too much stuff!)
But could also be that when you add powder to drawer, does some spill into the bit that you add conditioner? As conditioner is normally run through the wash towards the end of cycle and if powder was added then, it would have less time to be rinsed out.
Also, the rubber seal to the washing machine can have a build up of residue, try giving the seal a clean.
Hope that's of some help.

have you done a 90 degree maintenance wash and cleaned out the drawer, filter and rubber seal?

After much much testing I found it was overloading a quick wash so pretty easily rectified once I realised !

Thanks everyone. I expect I'm overloading a quick wash as suggested.

V grateful.