EASA isn’t UK CAA, or the other way round, but each EU State has responsibility for safety oversight and promotion. EU makes the law; EASA generates rules / specs, etc; EASA / State National Authorities implement the safety activities.
Most aircraft manufacturers publish ‘actual’ landing distance; there are several views of what ‘actual’ includes. The AFM certification distances are the theoretical ‘unachievable’ minimum. Boeing provides their version of ‘actual’ in the QRH which makes many assumptions, adjustments, and additions, this distance probably is the absolute minimum that a pilot could achieve, but for some operators the QRH includes a further 15% margin. The FAA refers to something similar in SAFO. I am not familiar with what Airbus publishes.
The numerical example is a classic ‘can we do this’ question, as opposed the primary, and overriding safety question, “should we be doing this”.
The answer depends on the situation; in abnormal / emergency situations some additional risk can be tolerated – you have to know what the risk is and what the acceptable limits are.
In normal operation, the risks of landing should be minimized with good planning and practice – the process of safety; the UK CAA guidance provides an acceptable method of achieving that objective, which can be applied to a range of landing operations.