Eggs Benedict using Goats milk butter Hi I'm a new user to the group, having just used the Hairy biker recipe for hollandaise sauce as a treat for Sunday brunch eggs Benedict.

This are the ingredients: 


225g/8oz butter, cut into pieces
4 tbsp white wine vinegar
1 small shallot or ½ banana shallot, peeled and very finely chopped
10 black peppercorns
1 bay leaf
3 free-range egg yolks
a pinch of sea salt flakes
a pinch of caster sugar 


And this is the preparation method:


  For the hollandaise sauce, melt the butter slowly in a medium pan over
  a low heat, stirring occasionally. Remove from the heat and pour the
  butter into a jug. Add enough water into a medium saucepan to come a
  third of the way up the sides. Bring to the boil, then reduce the heat
  to a simmer. Put the vinegar, shallot, peppercorns and bay leaf in a
  small saucepan over a high heat and bring to the boil. Cook for 1-2
  minutes, or until reduced to two tablespoons of liquid. Remove from
  the heat. Put the egg yolks in a heatproof bowl and place over the pan
  of simmering water. Whisk the egg yolks with the salt and sugar until
  pale. Pour the vinegar mixture through a fine sieve onto the yolks and
  continue whisking until well combined. Slowly add the butter in a
  steady stream whisking constantly until the sauce is smooth, thick and
  shiny.


It split terribly and would not be rescued by adding it to a new egg yolk whisked in a clean bowl over a pan of simmering water.
I had to use goats milk butter as I have a cows milk allergy. Would this make a difference? 225g of butter seems an awful lot? The taste was fine.
It's hard to know exactly why your sauce failed, but I can think of two main reasons-- first, your heat was too high; and second, you added the butter too fast.  The use of goat's milk butter should not be a problem, and the amount was fine.  Next time, here are a few things to try, if you haven't already:


When adding the butter, drizzle it in with the smallest stream you can, while whisking as vigorously as you can.  The rate of addition is critical; going too fast will overwhelm the process of creating an emulsion.  It is easier to do with two people, until you are comfortable with the technique.
Keep the heat down.  You need the water to give off enough heat so that the butter stays melted, but not much more.  For that, the water can be just short of a simmer (60-80C/140-176F).  If your water is boiling, you may never be able to keep an emulsion. 
In fixing a broken sauce, technique matters.  Be sure the extra yolk is well beaten before adding the broken sauce.  Next, drizzle in a little buttter to start the emulsion.  Then, as before, drizzle the broken sauce into the yolk very slowly.
Try adding a little water, say, 1-2 tbsp.  Too high a proportion of fat to water will overwhelm the emulsion.  I don't think your recipe is clearly out of proportion, but the amount of water is low enough to suggest it might be tricky to keep the emulsion stable.