Deposit not protected

[Guest]

I would like your opinions on something. When mum died of Coronavirus herein April, were 2 months left on the 12 month contract on her flat. 2 months notice was required anyway. I spoke to the landlord who offered condolences etc, but when I asked if we could make it the last month's payment given circumstances, he just ignored me. So even though it felt very off and in bad taste I paid the 2 months rent amounting to £1400. Now trying to get the deposit back, mums mobility scooter damaged part of the wall, which I admitted but he's trying to say she did more damage, even holes in the wall that were there before she moved in. He is trying to take half the £700 deposit even without accurate proof of the work on area of wall mums scooter damaged. He just got the whole place redecorated and cleaned the carpet professionally even though I had done this too a good standard. He said just pay half. But I'm not happy at his attitude and don't agree with some damage, that mum did not do. I discovered the deposit was not protected so I'm considering taking him to court over this. I am conflicted in whether I'm right or wrong. But I feel that is a good way considering he took 2 months rent from a dead lady and then even accused her of damaging things she did not! She is not here to defend herself. It's not about money but principle here. Am I right to make a claim in court? What are my chances of winning if a landlord hasn't protected a deposit dating to June 2016? Thanks