The Duffoins Go Home started with a vague idea of The Doctor helping a group of aliens go home. At the time they didn’t have a name, or a location. I thought somewhere in London would do, and I found a 1960s picture of the Old Kent Road and decided that this would be the place AND the time for the opening of the story.

From there, I had the idea of The Doctor coming across a group of youngsters with a den and an active imagination, something on the lines of the Secret Seven – the Enid Blyton series for those a bit too young for the Famous Five.

From there, I hit upon the idea that one of the children might be somebody The Doctor knows. Jo Grant was supposed to be nineteen when he first met her in 1971. That would make her 11 in 1964. I imagined the pre-teen Jo as a bit of a tomboy, with a sense of adventure and a lot of courage.

But the den would not BE on the Old Kent Road, so out came Google Earth and I looked for a nearby park. And I found one. And it was an absolute GIFT. Burgess Park is not the prettiest park in London, being neglected and forgotten for most of its existence. And that was exactly what I needed. A piece of land where the children had free rein, and where something a bit sinister might happen. The lake was perfect for that, and there was even a ready made ‘den’ in the old lime kiln.

The two children turning out to be Duffoins was a late idea. It helped to bring the children and the aliens together rather than them being two separate groups in the same adventure. It gave the children a good reason for wanting to see them off on their journey.

http://en.wikipedia.org/wiki/Burgess_Park

http://en.wikipedia.org/wiki/Old_Kent_Road