Okay, got five minutes –
What you described: Thames, writing – all good stuff. Water is excellent for removing things. One of mine is to send things into stones and drop them in fast flowing water – or stand in fast flowing water. I’d suggest doing it on the full moon so that after that it’s waning – taking it away.
If the issues are to do with sexual abuse (which is often the case with very bad things we can’t let go) then that’s a different matter and there are more specific but long-term rituals for that one. You need a whole battle plan rather than a simple banishing

It very much depends how strong these things are. The above banishing is worth a shot and between two of you may well be stronger than if she did it alone. It may well work – give it a go.
If not, get back to us, there’s plenty I could suggest but always play out your gut instincts (water, moonlight, writing) first – often spells tell you what you need to do. Be happy if it works, don’t worry if it doesn’t – magic can sometimes be a process of elimination