I’m not saying this is the one referred to in the SPC but this is the only one I have seen. I bought it from a lovely old chap ca 10 years ago at Stoneleigh, UK. He was selling his MKV Saloon and everything related to it. He said he used it only once to tow a caravan to the races at Goodwood. I forgot to ask which decade that was but surely over 50 years ago.