There are generally no limits on how much legitimate cash you can deposit into a UK bank account, provided the funds are from disclosed and earned income. However, banks have reporting obligations to the Income Tax Department for accounts exceeding certain thresholds. These reporting limits are distinct from deposit limits and depend on the nature of the account holder and the source of the funds.
You can deposit how much ever you want if it's legitimate and earned or saved from legitimate disclosed income. The other limits are the reporting limits which when crossed , the bank will report that account number and PAN to the Income Tax Department