Many thanks for your patience. The matter is not as simple as you may believe it to be. For example, it is not just an issue of, you were contracted to do a specific number of hour but worked more than that so should be paid for the extra. Under law there is actually no right to be paid for overtime. This you can get confirmed here on the Government advice site:
You will specifically see that the following points apply in UK law – your normal working hours are those hours defined in your contract. Employers do not have to pay workers for any hours worked on top of these normal contracted hours. If overtime is to be paid, then it would be stipulated in the contract. If there is no provision for overtime in the contract, then no overtime is payable, even if the worker does more hours than what they are contracted to do. The only right is that on average the worker is paid at least the National Minimum Wage of £7.20 an hour when taking into account the total hours they have worked and the total amount they were paid for them. As a doctor, I very much doubt that the total pay you received and the hours you worked would have amounted to you receiving below the minimum wage.
So as it stands, unless your contract guaranteed you a rate for working overtime, there would be no legal right to expect such payments. If you did have a rate for working overtime and you did do such overtime but were not paid for it, then you are able to take this further and seek compensation for this outstanding amount.
This is your basic legal position. I have more detailed advice for you in terms of the steps you must follow if you decide to take this further, which I wish to discuss so please take a second to leave a positive rating for the service so far (by selecting 3, 4 or 5 stars) and I can continue with that and answer any further questions you may have. Don’t worry, there is no extra cost and leaving a rating will not close the question and we can continue this discussion. Thank you