Same coolant pipe burst on my classic about 2 weeks ago.
Started the car from cold and was looking for the source of a tiny oil leak the car currently has, when suddenly all this coolant came rushing down the block.
On closer inspection, it was the exact same pipe you have pictured above, however the hole in my pipe was smaller and definately from the previous owner using a crappy jubilee clip which had cut into the pipe and rusted which eventually caused this 1inch hole.
Have you priced a new pipe yet? I paid £30 including vat for mine from Subaru in Penicuik!