Costs for a garden pond

Hi Everyone

I would like to have a pond in my garden, and I've just had a quote from 
a pond specialist which strikes me as rather expensive. It's for a pond 
approx 11  x 9 ft, about 2 foot deep, surrounded with rocks and with a 
filtration system, at a cost of about £10,000. The chap who gave the 
quote sounded very knowledgeable and showed some lovely photos of other 
ponds he'd done, and I'm sure he'd do a good job, but it strikes me that 
this could be a lot more than is sensible to pay for what I would have 
thought was a reasonably straightforward job.

Am I underestimating how much work is involved in digging a pond, or is 
this quote really very high?

Any thoughts gratefully received. Also any suggestions for other pond 
specialists in the south London/Surrey area gratefully received.

Thanks

Adam