Can I put my HD into an enclosure boot into it and expect all my apps / programmes to run?
The nice thing about macOS is that, so long as the machine you're transferring the drive to is old enough to recognise the OS on it [which it sounds like yours is], it will boot - &amp; you wouldn't even know you'd changed machines.

I migrated my Mac Pro 3,1 to a 5,1 by simply doing that - swap the drive to the new machine. Done.