I have the same problem at the end of May this year.
Fortunatley the hole was far enough away from the block that the mechanic who works at the dealer where I bought my Bongo from was able to (can't remember if he cut the end off the metal) push the hose on over the hole and secure it with a jubilee clip. He then pressure tested it for 2 hours - all ok, and I have had no further coolant leak since then.
We couldn't work out how to change the manifold if would have been necessary as the mechanic didn't think it was a screw fit.
The best bit was the repair was done free of charge
