I noted at the end of the service that the text of the hymn read "Hail him as thy chosen King" while the singers seemed to be saying "blessed King." I was not familiar with either, having always known the phrase as "matchless King," and one of my early work colleagues used that term whenever he required a light from somebody (not me!)
Listening to the repeat, I was doubtless wrong - I suspect that the congregation was indeed singing "mätchless" in a most refined accent!