What are ways of installing Python 3? In short I'm looking to install Python 3 (have a programme that on one of it's recent updates no longer ran with 2.7) I have Homebrew installed (but am not sure how I did it e.g. by Sudo I think?) and am looking to upgrade 2.7 to 3?

For full clarity apparently it's the OpenSSL module which needs upgrading specifically.

What are the ways of doing it?
As you already seem to have Homebrew installed, a simple

brew install python


should do. It will put python3 into /usr/local/bin so it shouldn't lead to any conflicts with the default installation.

PS: This is just for installing Python 3 though, not sure it solves your OpenSSL error.