Just a thought...

I have a Defender TD5 and I don't have an AC pump installed meaning there's a space on the engine where the pump can be bolted on and run off the serpentine belt.

I've got an AC generator motor lying in the garage from when I took apart a small petrol generator with mains (240v @ 50Hz) output.

Providing I make a bracket and ensure it's spinning in the right direction etc. Does anyone think this could work? I could have a small inverter that will run off the battery and power small things but I'm sure this generator could successfully power much larger appliances (obviously when th engine is running)

Opinions please?

don't think it would work,
gennys have a set "speed" to run the generator bit at to get the right frequency output, the varying revs of the engine when running would potentially damage connected equipment and/or the generator itself the wrong frequency can have more spectacular effects than overvoltage.

Why not? The army did it. They have a 24v genny mounted where the ac pump would normally go

24V DC not ac though wasnt it? AC rectified to DC doesnt matter about the RPMs, if your running straight off the AC it does.
AFAIK they used 24V to keep current demand down.

Ah good point, it would be DC

Thanks