It's a Wellington (or Wellesley). Probably a deadlocking latch. A very useful type of lock but rarely seen now.
I have some in my collection
It is supposed to have an easy and quiet action because of the rolling ball, and, because of the large aluminium bolt, be stronger than a typical latch.
An old design but there might be occasional stock from old lock companies, or Union, who took over Wellington many years ago.
IIRC the strike plate is just an ordinary latch type, with the angled tongue to lead the bolt into the door so it then drops into the gap once the door is shut.
The cheap thin type of strike plate used with common tubular latches is probably not big enough to fit the entire bolt. You may have to get your chisel out and fit a better one from a sashlock.
Bathroom and bedroom doors usually have a thin pressed steel one. If this is an external door or you want a strong and quality job, you could use the keep (staple) from a mortice sashlock. You will have to chisel out the frame more if it is the box type.
You can probably pick one up on ebay, or from anybody who fits doors and locks, or pulls them out to fit an inferior plastic door.
