Never heard of people who've left getting back pay before. I stand to be corrected bug I'd say you were out of luck.
They are legally entiteld to the backpay. But they have to claim it.
It's all here. Rumford v York city Council.
The simple explaination.
Employee has contract with employer. Employer has to pay for all work at the rate agreed ,even if the employee has left the company and the pay award is then agreed.
The defualt postion is payment must be made in the absence of any agreed (with the employee) to forgo the pay award if the leave the company before the pay award agreement is reached. See next paragragph.
Even then it is disputable becuase the statutory provisions under the wages act protect against dodgey contracts, in the case of Rumford v York City Council the Council failed in their attempt to prevent the pay award paying paid, even when they had a clause stating no payments would be made to employees leaving.
The judges findings are clear, the employer has to pay up.
Case.
ttps://assets.publishing.service.gov.uk/media/6465d8f3e14070000cb6e167
/Rumford_v_City_of_York_Council_1800201.23__1800203.2023___1800204.2023_judgment.....pdf
Read Par. 61 onwards.
Conclusion at the end No. 84.
For these reasons, therefore, the claimants’ claims that they were subject to
unauthorised deductions from wages are successful and the respondent
must pay Mr Rumford the gross sum of £577.50 and Mrs Rumford the gross
sum of £641.66.
Judge Miller.