Hi John,
BTW I noticed your address - I am in Warrington, but exciled Derby lad!
Anyway, there are a few composite organs around. Louis Huivenaar of the Netherlands recently sent me some phots which look quite modern of a compined reed/pipe instrument with pipes said to be by Harris and Son. I could send you a copy. Unfortunately I don't have much information about who built it or where it is now...
Regards, Rob