Just bought NIGHT WATCH and watched it tonight when it arrived. I don't think I've seen it since, say, I was a teenager and it was on the late show!
But it's a Taylor film no one talks about.
I actually think it's great, in its way (but, as with every Laurence Harvey movie he does with Taylor, I always want to re-cast him with James Mason).
Anyway, yes, I think it's a smidgen underrated. And has a nice, London-y, shrouded early-'70s melancholy flavor and that neo-Victorian early-'70s thing what with the dark wood and the plush velvet-y furniture and the Tiffany lamps and the overgrown plants and deep shadows and the sprinkling of harpsichord in the score and the occasional fish-eye lens.
Great twist ending, too!