Herston Rise is on Tilly Green, which is on the edge of Swanage proper. It's a terraced cottage, Grade II listed, so the walls are thick and the layout is old-fashioned. Sleeps four in two double bedrooms. One bathroom with a shower over the bath.
It's got a 3 Star rating, which is fair. It's clean and it works, but it's not modern. You can park right outside on the lane. The garden is enclosed, which is handy if you're bringing dogs. Actually, I should mention, we do allow up to two well-behaved pets.
The wood burner is the main feature inside. It heats the whole place up nicely in the winter. There's a washing machine and a TV. Wifi is there, but it's standard broadband, so don't expect to stream on three devices at once. All the bedding and towels are included.
For practical stuff, the local shop is a couple of minutes walk. The pub, The King's Arms, is basically next door, about fifty yards. They do food. The beach and the town centre are about a mile's walk down the hill.
In terms of things to do, you're on the edge of the Purbecks. The coast path is right there. Durlston Country Park is about a ten minute drive, good for a walk with views. Corfe Castle is fifteen minutes by car. If you drive for half an hour you can get to Lulworth Cove, Wareham, or the Tank Museum at Bovington.
A couple of useful links if you're planning: National Trust Dorset and the Durlston Country Park site.