I used to work in debt recovery years ago.
I mean this in the nicest way possible but you don't appear to be able to address this on your own.
Contact stepchange or any other free money management advisory. I'm not in the UK so don't know who they are. Ask them to negotiate on your behalf.
You have a relatively small debt but with an extortionate interest rate which left unaddressed will spiral to unmanageable levels.
If I was acting on your behalf, I would be asking Littlewoods to take into account the significant stresses in your life at the time, caring responsibilities, moving house and bereavement. I would be asking for leanincy and the surplus interest to be waived due to the mitigating circumstances.
It's not unreasonable to think that if your circumstances hadn't been so stressful at the time, that you would have managed things differently.
I think going back to the initial debt is reasonable and accepting a payment plan is reasonable, given the fact you have closed your account, are taking responsibility for the debt, are a co-operating borrower and are proposing a meaningful reduction in the debt monthly.
You need to find someone with the experience to do this for you.