OWD, Very smooth in action: you wouldn't know that it wasn't a Purdey bolt without looking. In fact, because of the 'hold-open' it is easier to close as you aren't having to cam a bolt.
Yes, an 'interesting' job to rejoint and we will find out how 'interesting' quite soon!
Once together, it looks like any other underlever backaction Woodward of the period. Lots of original CH though which I didn't discover until all the ancient oil 'varnish' and c**p had been boiled off.