The bank is authorised by the Financial Conduct Authority (FCA) and you do have rights here. The only way to resolve this is with a complaint and then go to the Ombudsman.
Given the dispute with the bank you can avail of the Financial Ombudsman Service dispute resolution scheme - which is much quicker than court action and free to use. You have to go through a complaints procedure first.
You have a right to expect a service (from the bank) carried out with reasonable care and skill. Furthermore, the account service should be “fit for purpose” and “as described”. If it isn’t then you can allege breach of your consumer rights and breach of contract.
You should now make a formal complaint and if that does not resolve the matter ask them for a "deadlock letter", which is a letter giving their final response. You can make the complaint here: https://www.tide.co/faq/complaints/
When you make the complaint tell them you will report this to the FCA due to their conduct. You can reach the FCA to report the insurer on 0800(###) ###-####if you wish. It may speed matters up.
Once you have the deadlock letter the next step would be to escalate this to the Ombudsman - they will investigate and liaise with the bank which would hopefully result in a reinstatement of the account. They can order the bank to make a financial award for inconvenience if they have acted poorly.
Once you have their final response, you can make the complaint to the Ombudsman here : www.financial-ombudsman.org.uk
Or by email:***@******.***
Based on the circumstances, assuming the bank does not uphold your complaint, I am sure the Ombudsman will do. The Ombudsman will look at this case independently and will make a decision based on what happened. Their decision is binding on the bank.
If the Ombudsman did not find in your favour, therefore, you then have the option of suing the bank for breach of contract and you have up to 6 years to bring a claim to the court (the limitation period is 6 years from your date of loss, to when you need to issue a claim). This is considered as a last resort though - I am sure the Ombudsman will resolve this given the facts.