The controls in Blood are typical early FPS controls, spread across the keyboard, no mouse look or even mouse turning, and pretty horrible as a result. Is there any way to change them? Booth Google and prodding at the files have failed me.

Also if its the same as duke3d and redneck rampage mouse look is toggled with the U key.

There is a setup option in the ingame menu, you can change everything there. The "u" key indeed toggles mouseview.
Beware though, selecting an already mapped key does not remove the alternate mapping. It is very well possible to map 1 key to 2 or more actions. Check is every keystroke is unique.

You might also want to check out this thread to help you get better mouse look.

You don't need to edit files around, you can change them directly inside the game
Options > Controls > Configure Keys...
to enable Mouselook press U (the default key) inside the game. keep in mind that the Build Engine doesn't use real 3d, it works a bit like the Doom engine so the perspective looking up and down is not correct, it looks a bit weird.
Remind also to set INVERT MOUSE AIM to ON if you want the mouse aim used on every modern fps.
Set mouse sensibility to max on the game options and then remap the keys to
W / A to move forward/backward, A/ D to strafe and so on.
Remind to clear duplicated keys before confirming the settings or you'll have a single key that does multiple actions.
Happy bloodbath!

Thanks, you saved me from making my own thread.

Thank you all for the helpful replies! What a wonderfully helpful community. :)

Same here. Thank you very much for quickly solving my issue.
Having a blast playing this game, fond memories.