So i just played through Q2 and the two expansions and fancied checking out the botmatches.

launching the game, i click on EraserBot and it loads up a game in which there is respawning kit etc but there are no enemies.

The options allow me to set up a player and play online, but i can't find any options for setting up a botmatch.

I can't find any helpful read-me either. Can anyone give me a plain-english guide to setting it up?

Yes, the documentation about this isn't well visible.
There's a readme in "Quake II/Eraser" which says

From within the game, type "bot_num X" to spawn X number of bots.

It's supposed to be written into the terminal which comes up with ^

In order to properly use the multiplayer mode wiith full controls, you probably want to take a look at the commands:
[url=https://www.eecis.udel.edu/~portnoi/quake/quakeiicom.html]https://www.eecis.udel.edu/~portnoi/quake/quakeiicom.html[/url]

The most important command being "gamemap" in this case, I think.

Edit: Tested, works.

Thanks i'll try that out when i have a minute...