Speakers with split crossovers are the easiest to setup for bi-amping. Yours clearly have them with its separate inputs.

You can do it with a split output from your preamp to drive both amps, then set their volumes to get a good balance between bass and mid/treble. You can use a dB meter or even a phone app to get it roughly right.

If you're using integrateds, you will need a variable line output (not the fixed tape outputs) from Amp1 into the CD or auxiliary input of Amp2. Then set the volume on Amp2 to get the balance right and use the volume on Amp1 for everyday volume setting.

Be sure you are not using a fixed line level output or you will not be able to control the total volume properly.

Much simpler with amps that come from the same maker as they will most likely have the same voltage gain, so no faffing about setting levels. This is why I brought up the idea of doing it with two AR amps Chris.
I've been bi-amping for almost twenty years, except for a short spell when I tri-amped!

Ok, let's try it like this:

1) Buy two 'Y' phono splitters (one plug to two sockets) and plug them into 'Pre-out' sockets of Amp1.
2) Take one set of interconnects, connect them between one leg of the Y splitters and the Amp1's own 'Power in' sockets.
3) Take the other set of interconnects, plug them from the other legs of the Y splitters to the CD or Aux inputs of Amp2.
4) Connect the speakers outputs from Amp1 to the speaker mid/treble terminals, and the outputs from Amp2 to the bass terminals.

So now Amp1 controls everything and Amp2 is the slave.  Use Amp2's volume control to set the balance between bass and mid/treble and then leave it alone.  You can do it by ear if you like.
Control everything from Amp1's volume control.  Connect all the source components to Amp1.

Ah,damn,the 8P doesn't have a volume control

That's a potential problem. You could try and see if the amp gains are close enough.  Just make the 8P Amp2.

Which brings us back to the AR power amp that I mentioned - it matches the gain of Chris' superb A-07 integrated, is still only £145 and I think it would do a better job than anything made by A&R (with or without Mr Arcam!) 

Sometimes it's worth remembering when you are up to your arse in crocodiles, that the original objective was to drain the swamp.

Bi-amping can offer benefits in some situations, but is not always better. That is to say that it is not true that any biamp is better than any conventional arrangements, and certainly not to the point where you add artificial crossover elements of the cheap integrated amp volume control variety. 

So it's best done with matched power amps

The alternative 1 off solution is get a Inca Tech Quatra it was design for that reason. Some are being sold all over e-bay in resent days.

I comes in a few shapes and manufactures.

Please explain that idea further and how could that be applied to a active system if indeed it could.