At the moment it's in Adobe RGB. Should I try Wide Gamut to see if it's different when I transfer to PS?
One thing that might really help is to know where DPP places the TIFF files it creates when transferring to PS.
I've done searches throughout the computer and can't find them. It's very strange. When I try 'Save As' in PS, the default location is a folder called "Digital Photo Professional", but the only folders of that name on the computer belong to the application and contain no images. Yet somewhere there is a folder that has a number of files I've converted from DPP to PS. (PS allows me to open them in Open Recent.) If I could find the ones that DPP has made, I could delete them, and start the transfer process again in the knowledge that it is not just defaulting to the old version before I changed CMS from sRGB to the Monitor Profile, as Panopeeper suggested.