the wordplay later; as ever, cheers to the setter for avoiding "regularly". 15   DE MON,T(F)ORT - DEMON=enthusiast, TORT=wrong and F=following. The reference is to Simon de Montfort . 18   S(PEA, KILL)OF - the vegetable is a PEA, KILL=end, and the sofa is actually SOFA (though leaving out the "a" as instructed).