For those employees who have very physical jobs, can we automatically require a medical assesment before agreeing to requests to work beyond retirement age?

No. One of the key principles behind the legislation is that you should not make assumptions about a person's capability based on their age. It is likely that automatically requiring a medical assessment as part of the consideration of whether the employee can continue to work beyond retirement age will amount to less favourable treatment on the grounds of age unless it can be objectively justified. So you should disregard the fact that an employee has reached retirement age and consider whether you have any genuine concerns about the employee's health which would justify asking them to undergo a medical assessment.  more