Just found the Bluetooth keyboard case I bought to use with the Android tablet I bought in amoment of weakness a few years ago. It's not intended for use with the 5th gen iPad but it can be made to fit.
It works but the spacebar requires a very firm press to register.
Not worth the bother. In future I'll use the folding Bluetooth instead: its keys are bigger (whole keyboard is wider) and don't have the rubbery feel of this POS.