On 2013-12-07, polygonum wrote:

Mr Medway or anyone else, do you have any advice on removing blood marks
from off-white wool-blend carpet?

Although quite some attempt was made to clean them up at the time,
various circumstances have resulted in them still being visible some 3/4
weeks later.

(No criminal aspect to this! Illness, unfortunately.)

Hydrogen peroxide (probably still available from your local
chemist's). As with any cleaning tactic, it's worth testing a little
of it on a hidden area first in case your carpet disagrees with it.