Staff were excellent, friendly and helpful. Food was very good (both breakfast and dinner). Room was a bit noisy largely with chatter and laughter until 11:30 p.m. - but it's a pub, so can't complain but after that time it was all very quiet. Bed was quite comfy, shower was excellent, notes on what was complimentary or not plus costs were very useful. Very clean and tidy. Nice restaurant, which is in a separate room from the pub, and pleasantly furnished, tables for two charmingly arranged so you sat adjacent not opposite each other.
Be sure which Devonshire Arms you book - confusingly there are 3 in the immediate vicinity - two are part of the Chatsworth Estate I believe - so easy to rock up to the wrong one - as we did.
It is well placed for Chatsworth House - it's proximity is the main reason we chose it but be warned - taxis charge from the nearest town, not from the pub so though it is only 1-2miles drive or walk to/from Chatsworth if you are going for a wedding and you are in your finery it'll cost you £10 there and, if evening, £20 back (with the discounted rate) not a fiver each way which is what the distance would suggest. Walking to Chatsworth is only safe across the fields - no footpaths on the twisty roads.
Overall, fair to say accommodation is a tad expensive, but the restaurant was good value and staff beyond price!