My one, somewhat incomplete but functional, referenced in the pictures below, probably looked like this when it was new:

Quote:

This is the GECoPHONE Crystal Detector Set No. 1. Built by GEC (UK) in 1923, this simple crystal set is housed in a polished mahogany case with lift up lid and ebonite control panel. It bears the ‘BBC’ stamp and P.O. Reg. No. 102. Connection points for the aerial, earth and headphones are provided, and the controls comprise a tuning knob and a lever to adjust the detector. The set would have cost £5 10s in 1923, of which 7s 6d (6.8%) was a royalty paid to the BBC. Having no valves in the circuit gave a considerable price advantage. In 1923 the Marconi company received a royalty of 12s 6d for each valve used in a set.