tyres

Cross is a bit traditional inasmuch as its unusual to "mix" tread, i.e., if you've got a Rhino on the front you'll find the rest of the grid pointing and asking questions if you have a Typhoon on the rear.

On the other hand, this has been going in mountain bikes for a long time - very common to put something with more grip on the front matched with something faster in the rear. Theory being that unweighted front needs more grip (esp as front wheel wash out harder to rescue/more catastrophic than rear wheel wash out).

I think its a good idea on the right course.

I would have thought off road you'd want the good grip at the front for the very reason above. I think from the little I have gleaned about cyclo cross tyre mixing this is the way to go. There's a discussion here:
http://cowbell.cxmagazine.com/forum/topics/mix-and-match-tire-treads

but it doesn't sound cut and dried from a reacer's perspective.

Did this recently whilst waiting for a wheel build. Rear was knobbly, front was slick (Gatorskin). 32mm tyres. Coped OK with gravel tracks but I was cautious about pushing the front. If I was to run it permanently I'd want more grip at the front as its much easier to control the rear stepping out of line than the front tyre washing away (unless you're Marc Marquez)

That sound bonkers, however that tyre you've brought isn't that knobbly, so you'll probably live, just about... 

However I'm not sure having the knobbles on the front is better than on the back.. might want to think about the type of riding you do before making that decision, more weight on the back most of the time. 

Frankly I'd say spend the £20 and get another one.