Consideration should be given to whether reverse parking is the most appropriate means of parking in specific bays.
Should a risk materialise as the landlord/owner, you have a duty to ensure that the risk is appropriately managed. For example:
Where any incidents take place, a risk assessment should be carried out, and a management plan should be created to reduce the risk of recurrence.
The HSE provide further guidance on making car parks safer: Parking - Workplace transport - HSE