Spend more money on the amp or the pre-amp?

Agree with those who say "integrated" and add a further wrinkle:

The more efficient and sensitive your speakers are, the better a cheap amp is going to sound.  People with K-horns report great results from TPA3116 chip amp boards (which have volume controls); I've paired one with some 91db/1watt Dahlquist DQM 9s and while the sound could obviously be improved on, the results are super suggestive of what could be achieved in this manner.

You stereo is a system; build it like one.

 

I would speak to your local dealer and visit him. He will treat you with respect and even more respect your budget whatever that may be. Build your systems with respect. Happy listening my friend.

preamps are obsolete, just use digital volume control ;)

IMHO, the "separates are always better" mantra is at least 30 years out of date. Two advantages: 
Value for money: you're not paying for interconnects, another power cord, another chassis, and more packaging (it's amazing how much the latter two account for the wholesale price, especially at lower price levels). 
Performance: I believe that lot of what makes a system more "alive"-sounding comes from lowering the noise floor. Bad grounding and impedance mis-matches play havoc here; an integrated eliminates pre/power interaction problems by construction. 
Advantages of separates include automatically separate power supplies and easier shielding, but in my experience skilled designers can now make integrateds competitive with separates at prices well into five figures.

Update for anyone interested:

Got a Rega Brio-R off Ebay ($430) for the KEFs.  Sounds fantastic.

Got a NAD 7175PE off Audiomart ($170) for the Wharfdales - sounds really great.

Thanks everyone for all the thoughts and ideas - really helped me to sort through things.