Hi Hashem,
It is great that you are considering studying with the Open University. I have not heard of the AHLEI Diploma in Hospitality Management. If your Diploma is at level 4 or above on the National Qualifications Framework, and within the last 16 years, you may be able to apply for a Credit Transfer.
https://www.gov.uk/what-different-qualification-levels-mean/list-of-qualification-levels
There is no cost to apply, and no obligation to study with the OU if you apply for the Credit Transfer. If you are planning to start your studies in October 2024, the deadline for credit transfer applications is 8 August 2024. You can find more information, and the application form, here:
https://credit-transfer.open.ac.uk/
The closer your previous study matches what is required on the OU qualification, the more likely that credit can be awarded. For example, previous study in Mathematics probably wouldn't be able to count towards an English degree.