In reply to jimtitt:
No, I`m not that light, but it was particularly noticeable on a static rope yesterday which was quite thick.
So solutions, next time when abseiling on my climbing ropes, try back to front, then try extra krab looped through rope and belay device loop but not harness belay loop.
Next time when abseiling on thicker rope, I will first try device in normal position with extra krab, then with back to front and extra krab.
Does this seem reasonable.
Thank you for the advice.