What age are your kids? Check this one out, www.strictlybedsandbunks.co.uk/appollo-pine-4ft-6-triple-sleeper-with-underdrawers I don't know how to add photos here, so I just added the link so you can see it. Seems to be what you are looking for. It has space if you want to sit and read a book, it can also be used individually as beds when they grow up. I love that the bunk beds has under-bed storage also where you can store books, toys, or extra blankets.
I bought the R11503 on the above page - although I think it was from a different website. I LOVE these bunk beds. My daughters were 4 and 3 when we got them, and they look beautiful in their room. Easy to assemble, I did it with my husband (and was pregnant at the time, so he did the more manual bits). We've had them just over a year now.
The beds are single adult size, which made DD2 look tiny when she came out of her junior bed. There is just about enough room to sit and read a book on the bottom bunk, although I am more comfortable leant forward as the top bunk sits a bit close to the head. But for the kids to sit under there and play it is more than spacious. The bunk bed is quite tall, but you need that for the space between the two bed. There is enough room under the bottom bunk to store toys and boxes. We have quite high celings so there is also loads of room on top too.
Ive never bought furniture online before but we are so happy with these bunk beds. They change into two single beds for when the girls are older and the wood quality is excellent. We paid more than is advertised on this website, but in my opinion they were worth every penny. Never regretted the purchase.
Am thinking of getting bunk beds for DTs who currently share a room. Want to be able to use the bunk beds as single beds, and also want a fairly large gap between the bottom bunk and the top bunk so that child in bottom bunk doesn't feel too hemmed in, and also there is enough room for adult to sit on bottom bunk with child to read bedtime stories etc. If anyone has a recommendation for something that would fit the bill, please let me know!