Thanks to both of you
I will post the pics when I get the old parts back from the workshop.
I quizzed the mechanic about the oil pump failure that he blamed for the broken crankshaft. I asked him how come the hydraulic valve lifters did not stop working before the crankshaft broke? After some squirming around in his seat, he agreed that the pump was still working but said that crankshaft was starved of oil by clocked oil ways to the area of the break. I can nolonger examine those oil ways, as the block has since been cleaned at the machine shop.
I do however, still wonder if this could be the cause, since running an engine dry of oil or an oil pump failure are fairly common things to happen to engines, but in my experience, it's the top end which suffers first.
It looks like we will be obtaining a good second hand crankshaft, 2 replacement second hand conrods, new piston rings, all bearings, bushes, camchain sprockets and cam chain. Also a new camchain cover, since although the chain did not break, the cover did. Also fitting new oil pump, plugs, and valve guides.
I drive like an old man due to the gas consumption, so I'm still amazed that this could happen at just light acceleration at 20km/hr!
Anyway, really appreciated your encouragement. I'm now sufficiently confident to have it re-assembled without thinking that it's going to break again the moment we turn the key!
Cheers guys, pete