Could someone please explain the difference to me between the 'freehold' of a property and a 'lease holder?

No.  They are unrelated.  Freehold is the property is owned, "free" & clear.  "Lease" hold is not ownership of the property.  It is leasing the property, and paying under that lease for a very long time.

The freeholder of a property owns it outright, including the land it's built on.

A leaseholder is someone who owns a property on a lease, typically for 99, 125 or 999 years. The length of the lease decreases year by year until it eventually runs out, additional  lease years can be purchsed to extend the leaseholding term and the leasholer can sell the property and remianing leased years, if the lease term runs out then the property reverts to being the fully owned property of the freeholder ( or heirs to the property). A leaseholder is also called a tenant, but this should not be confused with short-term agreements. They pay ground rent to the freeholder

ask the question on google stating the country you are talking about as that may change from place to place.

Most of the time when you rent the taxes are paid by the owner (freeholder) and they're not passed on the the lease holder.