Thanks again for speedy reply.
I was loathed to contact you again but I don't see what more I can do.
The download page has no link but states:
"Cadabra is now available in Debian 11 (Bullseye) from the official repositories, by installing the cadabra2 package (though this may not always be the most recent version). Thanks to Alex Myczko for making this happen."
I used synaptic to obtain cadabra2
dpkg -s cadabra2 | grep '^Version:'
Version: 2.3.6.8-1
Is there another repository I should be using.