#7 fuse location is empty and I want to add a device using this location. The black plastic fuse block is empty of any connector on the left side; a brown wire is terminated in the right side. 

What is the size/mfg-part number for the female connector used in the remaining fuse block locations. It appears to be a simple spade type connector which accepts a 5.15mm fuse ‘spade’.

Yes it is - but check that your new spade has a small tab/ear on it - this is what retains it in the fuse holder block. This is also the means by which you can remove spades - I find that a small flat blade jeweller's screwdriver, thinned out on a linisher/sander makes a good tool for this.

Have you tried a 6.3mm female terminal in there Chris? I haven't, but I don't think they'll fit because they need a 7mm wide housing. These are the originals:-

https://www.vehiclewiringproducts.co.uk/c-1-home/c-60-terminals/c-72-non-insulated-terminals/c-206-terminals-to-fit-mouldings/p-751-terminals-for-micro-and-standard-relays-6-3mm-blade

I think they're Tyco (ex- AMP) but I'm not sure.

Good point, I'll check later today.

I don’t believe a standard 6.3mm female connector will work...too wide. Also the 6.3mm is too large to securely hold the fuse blade. If I can find a 3-2050 (your URL) that will be the correct way to go.

EDIT: I used your information to find various manufacturers and came up with TE (Tyco/Amp) and they are sampling me four of their https://www.te.com/usa-en/product-964203-5.html

Thanks for the confirmation on the manufacturer.