Lichtgestalt - My Photo Index seems to fit the bill, I've been playing with it this weekend. I don't anticipate having several thousand keywords/tags and, like LR, MPI allows tags to be nested. MPI also allows you to select multiple photos using the usual MS ctrl/shift click and then drag a tag to the nearest selected photo and all the selected photos are tagged. One click per tag. Just repeat for each tag. I don't know yet how many tags are allowed per photo but I'm sure that I'll find out. I'm up to five at the moment and this is enough. So far I am very pleased with MPI.
MPI doesn't identify RAW photos but will open CRW and CR2 files. As the JPEG and RAW are set out in order it's easy to see which is which. I have my RAW photos in a sub-directory of a specific group. More importantly the database is an mdb file and is not huge, nor is a separate copy of the imported photos kept. My main concern now is that I spend a lot of time tagging years of saved photos only to find a nasty bug lurking in the background.
For a freeware program MPI is absolutely brilliant. I don't agree at all that you have to pay for a program for it to be good. For example Firefox and Thunderbird are, and always have been superior to IE. With a commercial product there is pressure to develop to the point of the program becoming unweildy and bloatware. There's plenty of rubbish out there. The current trend for annual charges for software isn't going to help.
Many thanks for your help and to everyone else.
P.S. I tried to download a trial copy of LR but wasn't able to.