Cash In Hand Employee Termination

In a cash business like the licensed trade, paying staff in cash is sensible (as long as taxes are all paid, etc). Paying cash into the bank costs money every time, writing cheques costs money every time. Banking £200 cash and writing a cheque would cost (on my tariff, for instance) £1.95 in bank fees (0.65% on cash plus 65p per cheque). I don't think we should read too much into the "cash" thing

She has a contract, even if it is not written. It sounds as though she is currently suspended.

This may be because they suspect her, it may be that they are hoping it will give the real thief confidence so they can catch them in the act.
How long has she worked there? If it is less than 2 years, they can dismiss her for any reason, or none (except where the reason is discriminatory in relation to a protected characteristic)

So they would not be under any obligation to show her their evidence or even to tell her whey they are choosing not to keep her on.

If she has worked there for more than 2 years then they ought to follow a proper disciplinary process,which would typically include telling her what the issue was and giving her the opportunity to respond.

Her changing her money using the till might well be seen as misconduct even if nothing were stolen. How do you know what the CCTV shows? Are you confident that it is clear enough that it shows she took out, and put in , the same about of money, or does it simply show her opening the till when there was no customer to serve, and taking money out?

If the police are involved, then if they decide to interview her as a suspect she would be cautioned, would be entitled to have a solicitor or legal rep. (an would be well-advised to get one) and they would have to disclose the evidence they have.

However, if the situation is that there were two thefts, one at a time your mum was working and one when she wasn't, I would expect suspicion to fall on whoever was there both times.