I'd be tempted to tile it, like a tile skirting. He'll obviously have access problems, but i think it'd give the neatest finish... If i'm visualising it correctly, that is. 😀
Pull the plinth off and smash it up....tell him it fell off and he didn't fix it very well..hopefully he has no more to replace it and he gets a some propper pvc plinth in white....:lol: