Does anyone know or experienced this type of engine failure?  

18 minutes ago, Awesam said:

Does anyone know or experienced this type of engine failure?  

In what sense? I've experienced a similar failure exactly once down the years (different maker and engine), and it was handled as "new engine under warranty".

it's happened to friends engine, one rod has come out the back of the block into the transfer box and another out the front.  It was on stand still, idling!

18 minutes ago, Awesam said:

it's happened to friends engine, one rod has come out the back of the block into the transfer box and another out the front.  It was on stand still, idling!

Well, I'm convinced this should be new engine under warranty (and new transfer box too by your account).

Its outside its warranty period.  I'm thinking maybe it was over revved whilst stationary.  

51 minutes ago, Awesam said:

Its outside its warranty period.  I'm thinking maybe it was over revved whilst stationary.  

That'll do it👍👍

Was there a teenager involved by any chance?

I find it strange that 2 gudgeon pins would give way at exactly the same time so that both con rods would go through the block even if being over revved. What engine is it?

It's a CJXA. The only other thing it could be due to a poor remap? 

Wrist pins don’t just fail on their own so it’s either down to bad servicing or a bad map on the vehicle.