In Austria I've seen panels partly made of wood well into the 1970s. My parents own a weekend home that received a new combo meter enclosure/consumer unit in 1976. The visible parts are all powder-coated metal but once you get behind the covers and frame it's a wooden box lined with asbestos. I suspect that might have been an ad-hoc solution on site because the wall is only barely thick enough to accommodate the unit, more commonly these enclosures were just open and you could see the plastered brick wall through them. I think completely enclosed meter cabinets only became a requirement in the mid-1990s so now there's usually a metal tub. Mind you, these things are large, most distribution network operators suggest three-meter enclosures for single-family domestic buildings, either for a night-rate meter and tariff switch or more recently for photovoltaic cells with a dedicated meter.