Richard Faulkner wrote:
Hi,

My house is around 100 years old, or more, and one of the hinges on the
front door has split. I am presuming that the door and hinge are either
original, or very old. It's a very heavy door, and a substantial hinge.

The hinge is 3.5 inches high, and 2 inches wide, (when open), and I cant
seem to find any sources of this size of hinge - any ideas.

Is there any pressing reason to replace the hinge with an exact match?
I'd start by looking in http://www.toolstation.com/ for a suitable hinge.
Possibly 4 hinges, and cut more recesses.