Apologies slight delay, I experienced some temporary connection issues earlier on. All seems to be resolved now so I can continue with my advice.
If you had a contractual right to be paid overtime at a certain rate but the employer failed to do so then you can pursue them of contract or unlawful deduction of wages. How far back you can go would depend on how long there was a continuous failure by them to pay you what you were due. If at some point you were paid the correct amount, then that would have put a break in the underpayments and you can only claim from that point onwards, assuming there was no other such break. So it is important to check if you were always underpaid. If you were never paid the right amount then you could potentially claim full period although you would need to prove that you were indeed underpaid that time so some documentary evidence will be required.
In order to try and resolve this, the employer should be contacted in writing, advised that this is being treated as unlawful deduction of wages and ask them to pay back the money within 7 days. Advise them that if they fail to pay the money that is owed, legal proceedings could follow.
If the employer does not return the money as requested, the following options are available:
Hopefully by warning the employer you are aware of your rights and are not going to hesitate taking further action they will be prompted to reconsider their position and work towards resolving this.
Hope this clarifies your position? If you could please let me know that would be great, thank you
yes that is correct and you must also show there were no 'breaks' as mentioned above, otherwise you can only claim time since the last break
you are welcome, all the best