My old employers are trying to charge me for internal training. I need advice, please.?

Hi,

I left my old employers in February. I was treated unfairly. I had an excellent 3 months probation review. Then at the 6 month stage they said I hadn't progressed and tried to scapegoat me. They said they would increase my probation by another 3 months and I'd have to do presentations on construction topics every week. However, they didn't paint it in a negative way in the meeting, just when I got home and saw the letter.

Long story short. I paid them the professional qualifcation fee back and the fee for not working my notice period. However, they're trying to charge me £450 for two internal training days and one of the training days pre-dates me signing a training agreement with them by 2 months?? Is it possible to charge for something that isn't in a contract or was before a contract was signed??