- They're just (elegant music) wonderful people to have.

James Herriot's son Jim and Rosie they're consultants on the show, so they'll read over some of the scripts.

It's just invaluable the stories that they have and chatting to them about the real James and Helen.

- I communicate with Rosie frequently.

Usually at the start of every season I check in and say, "This is where we're at.

Is there any sound bites you can give me?"

And she says she enjoys it.

She says she doesn't mind, so I'll keep doing it.

- Just little things as well, like we asked them, "Did they have pet names for one another?"

She said, "Not really."

The one thing was anytime James or Helen left to go on call or whatever it might be, they would always kiss.

Just little details like that, that we've been able to incorporate into the show.

And I think that those are just priceless, you know?

Those little details, those little specificities, just make it all the more richer.

- I'll see you later.

- Bye.

- Bye.

Rosie sent over that at this point was a very sort of fun point in the kids' lives, and Helen was always at the forefront of the fun.

Hello (chuckles).

James is pretty busy as a vet now, 'cause he was a partner in the practice.

So it was mainly all on Helen with the two children.

And it was a sort of struggle and a juggle, as parenting is.

- Even like at Christmas, you know, it's a very busy time for vets, and the animals never know that it's Christmas Day, so you're still out on call.

But he said, every year he still, his dad would always make it back for Christmas dinner.

They would always manage to get back just in time.

- I wanted to bring the chaos to everything and, you know, hopefully we do that.

It's very easy to do that actually when you are actually filming with two children.

It's pretty chaotic.

- In the books, James Herriot talks about Rosie being a little shyer and a little more cautious, whereas Jimmy was a bit more bold and bright and confident.

And he would swagger around in his little vet's uniform and he'd say, "Jimmy, you know, can you get me this, x, whatever it might be from the car?"

And before he'd even said the full sentence, Jimmy's off like a shot, striding through in his little welly boots to get the thing for dad, bring it back like this, proud as punch that he's managed to do it.

One of the things that's lovely about the books, he was an an older man when he was writing the books, but he wrote them in the living room with his family in the evenings after being out on calls and doing his job during the day, because he said if he then had to come home after a long day of being away to then sit in a different room from his family, then he wouldn't see enough of them.

So he wrote in the living room while they were watching TV or playing games or whatever they were doing.

And I think that environment and that coziness and love between them all in the family, I'm sure that has seeped into the books.

And they've also taken us around Skeldale house, you know, the actual practice in Thirsk, which is now a museum.

So that was the house that they lived in, grew up in, and was the practice.

And it is brilliant.

You get absolutely lost in that, and we've had the treat of being toured around it now by Rosie and Jim on separate occasions.

So they have so many stories about the real Siegfried and Tristan and about their mom and dad as well.

It's wonderful to have them as part of the show.

(elegant music continues)