Hello... The Lanchester ain't so well known, eh? It's interesting to note that one of the more solidly built SMGs for the Brits (and allies) was a direct copy of one from the other side. Looks pretty solid too. I'll certainly feel secure with this little beast as a home defense option today.
The Lancaster was bought by the Royal Navy for its Ship's Arms Rooms. Some may have found their way to the Royal Marines.