how to best remove version 10 (and keep version 9.5)

Hi folks

I am running an Ubuntu 18.04 lts remote box.

For some (complicated) reasons I did install PostgreSQL 9.5 alongside the
already installed V10 instance.

I did set the data_directory to point some disk  “outside” the standard
/etc/postgresql/9.5/main structure.

Now, what I would like to do is to get rid of one of the two installed
PostgreSQL versions.

Also there are aliasings like:     /usr/bin/pg_dump ->
../share/postgresql-common/pg_wrapper*

I would like to avoid them if possible.

Things are running now with version 9.5 so I tend to prefer to keep it.

The whole setup is kind of temporary and will be migrated to the “real thing"
during this year. So it is not a problem that the PostgreSQL version is dated.

I would be grateful for your help

robert