Mono/stereo headphones

I've got a bit of a problem at the mo. I'm profoundly deaf in me right lughole and I had a set of Sennheiser cans that I could switch to mono when I was listening to music and didn't want to disturb anybody. However, I foolishly lent me cans to one of my nieces for her gap-year in India, and she lost them there (or they were nicked). Whatever, I'm now effectively "canless" and starting to annoy various family members (especially my wife, who hates jazz in any form) with my music playing.

I've had a butcher's on t'internet, but there's so much info that I've become confused. Most of the cans seem to be stereo anyway, but some models have a mono switch. Unfortunately, sometimes these models are described as mono/stereo and sometimes they're not.

The mono switch on my Sennheiser cans was part of the little volume control thingy on the main cable before it bifurcates for the individual cans. Trying to get the same ones again is flogging a dead horse, since I originally bought them in 1979 (I know, I know!).

Any clued-up Scalies or such out there who could point me in the right direction? Any help would be truly appreciated.