The Duke of Wellington Hq is in the Old Town in Hastings. It's the first floor flat of a Grade II listed building. There's a blue plaque outside, which is a nice bit of history. It's literally just off the High Street.
It sleeps six, but as two bedrooms. One is a king size, the other has a day bed that can be made into a double on request. The third bed is a sofa bed in the living area. There are two bathrooms, both en-suite which is handy.
It's 5 Star, which means it's done up to a high standard. There's antique furniture around, but it's comfortable. The layout is over three floors inside the flat, so there are some stairs between the living space and sleeping areas. Worth noting.
The location is the main thing. You're a couple of minutes' walk from the beach, the pubs, and the shops in the Old Town. It's all right there. Parking isn't on site. You'll need to use the public car parks at Rock-a-Nore or Pelham Place, which you pay for, or find on-street parking a short walk away.
From there you can walk to the pier, the funicular railway up to the castle, and the Fisherman's Museum. The National Trust at Hastings Country Park is good for walks. For a day out, Rye is about twenty minutes drive. Eastbourne is about half an hour. Battle Abbey is also about half an hour inland.
Facilities wise: it's got a dishwasher, WiFi, TV, and all the bedding and towels are included. It says pets are welcome, up to two. You'll get a welcome basket with local bits when you arrive.