Argh! I hate to break it to you, but our old cream carpets were completely ruined in places by Calpol. They went sort of luminous orange colour eventually - and a professional clean didn't remove the stains
We have calpol stains on youngest ds carpet too from those middle of the night calpol doses when you are half a sleep and spill it everywhere. I've tried vanish carpet stuff with no luck so far. His carpet is cream too. I have a hand held steam cleaner and haven't really got on with it to be honest but mum has a big proper one and she swears by it. good for everyday dirt but no luck on stains.
You could try SEBO powder. It is I suspect horrible environmentally but it seemed to remove most stuff - including ink! I buy it in John Lewis with the hoover bags. You rub it in, leave it to dry and hoover off. Some stains take several tries - but sorry no experience with calpol!