With the latch open, you may be able to reach up and grab the broken pieces with with some pliers and pull down on them to open the latches. Not sure if the fix it after it breaks latch is still being sold or available but here is the link. MFG solution is to replace the entire top case to get the latch and it is still pot metal. I replaced my broken latch with this and it is far superior and less than a top case.The cylinder lock is ok its the latch that has broken at the top on both sides the latch it lifts ok but does not open the case.
I haven't a clue how to get the top open.
It dies not have central locking fitted.