Right, it’s called Horseshoe Lake 5. It's actually one of two pods on Chapel Fields Holiday Park, near Skegness. They're detached from the main park.
It sleeps up to six, which sounds like a lot, but that's because it's got a mezzanine bedroom up a ladder that kids tend to love, plus two sofa beds downstairs. So it's one proper bedroom area, but space for six. One bathroom with a shower. It's got a 4 Star rating, so it's recently done up and clean.
The main thing is the location. Your private deck is right on the edge of Horseshoe Lake, and you have your own fishing peg. You can step off the deck and start fishing. There's wildlife about. Parking is right next to the pod for one car.
Inside, it's a pod, so it's compact but modern. It has a kitchen area for simple meals, a TV, and WiFi. Bedding and towels are included. You can bring up to two dogs.
The on-site coffee shop is licensed. For a shop or a pub, it's about half a mile walk. The beach is a mile away. You can walk it, or get the bus from nearby. Skegness centre is a short bus ride for all the usual seaside things: amusements, shops, cafes.
If you're with a bigger group, you can book the pod next door, Horseshoe Lake 3, as well. That would fit twelve altogether.
For local days out, the Lincolnshire Wildlife Trust has good information on reserves and walks. For the coast and history, National Trust East Midlands lists places like Gunby Hall.