Found a copy of Ghost and Ghoul in a secondhand bookshop yesterday. I vaguely recall reading this as part of the original research for Apostrophe S and a reference is included somewhere in the voice over to Hangway Turning. Lethbridge has his 'Sons of T C Lethbridge' admirers though perhaps in Ghost and Ghoul he is less the detective suggested in the introductory blurb and more of a postulator. Far more on Lethbridge here.
