There are a number of sources of information available. Unfortunately, I can't recommend anywhere in particular as I have no knowledge of any specific places.

For B&B accommodation look here.

There are a number of Premier Inns in the area.

There are a few Travelodge hotels in the area. Ashbourne is probably OK, and in Derby I would stick to the one in Pride Park.

For other hotels take a look in Expedia - the postcode at Blackbrook is DE56 2DB

You could try here - the lady at Blackbrook recommended them, but I can't get much sense out of the web site. They do look rather nice though.