I have replaced a vial in a M&W engineers level and have used it a few times in anger, not the easiest thing to use I have to admit.
Then one day I had the proverbial light bulb moment. A few years ago, I was given an artillery clinometer as a birthday present, members of my family know that I value such offbeat things! This one was a MkV from 1943 , complete with leather case. Like Clive,I realised that this could be used as a level. I find it easier to use and just as accurate as my M&W level,
Andrew.
P.S. Similar artillery clinometers don't seem to be very expensive.