An Enduring Power of Attorney (EPA) made before October 2007 is still valid providing it has been properly executed. However it is important to regularly check the EPA to ensure that it has been drafted as you would want to presently, for instance in relation to who your attorneys are, how they act (jointly or jointly and severally) and the restrictions to which they are subject to.
If some aspects of your EPA are no longer relevant or you would rather draft it in a different way it is advisable to replace it with a Lasting Power of Attorney for Property & Financial Affairs, since your EPA cannot be amended.
It is important to note that an EPA only applies to your property and financial affairs and cannot grant authority to an attorney to make decisions in relation to your care and medical treatment. So even if your EPA is still relevant you can make a Lasting Power of Attorney for Health & Welfare should you later lose mental capacity to make those decisions.
It is also to note that an ORDINARY POWER OF ATTORNEY is no longer valid should you lose mental capacity after making that document.