Hitting the big time?

OK, so, new book out in August, new publicist assigned. The very lovely Julia suggests that I come up with one or two story ideas that she can tout around various magazines. No, the ones I've already written sporadically over the years won't do - the magazines have a specific brief. A particular length, upbeat, with a twist.
After much dredging of my subconscious resources for anything upbeat, I come up with a possible plot. Middle aged woman sees son off to university, left in an empty house. Looking forward to sporadic visits with much laundry.  The twist is that she's already booked her tickets to travel round the world in 80 ways.
Nobody likes this idea.
It's not that bad, I complain. But My Weekly have suggested that since I'm writing historical fiction, I might want to think about a story with a historical theme.
My weekly is number one for fiction publication, apparently, in the popular market. Circulation 110,000.
The trouble is, I've been here before. Asked to generate ideas for articles and stories that are then rejected.  The popular market is just as brutal as any other.
So I push the whole idea onto the back burner and get on with trying to finish the third novel in the Succession trilogy.
But over the weekend an idea comes to me that is connected to my novels, but which introduces the additional character of an anchorite.
I've been fascinated by anchorites for years: the whole idea of being officially 'buried', funeral rites said, then living the rest of your life walled into a cell.
Such fun!
But in 1483 there was an actual conspiracy to release the princes in the Tower, and this, together with the new character of the anchorite, forms the nugget of a plot in my mind.
Without any particular hope I draft two paragraphs outlining my idea and send them to my publicist. Two days later she gets back to me. They love it, she says. Can you write a sequel?
They want a two-part story, of 3000 words each. The deadline is Monday. It's Wednesday.
Still, nothing fuels the literary urge like having someone actually want your work. I roll up my writerly sleeves and get to it. Send the two stories off and they're accepted the next day! None of the waiting around for months that accompanies novel-writing.
In the meantime, the Sunday Mirror have expressed an interest in me writing a short story for them. This one has to be contemporary, and 1,600 words long.
The Sunday Mirror: circulation 1,800,000.
I write the story, which again is accepted that week.  I could get used to this!
The great thing is that all three stories will appear in the week of publication. Rebellion comes out on 13th August; the My Weekly issues on 15th and 22nd and the Sunday Mirror on 16th! And both will advertise the book and organise book giveaways. It's a writer's dream.
It's very hard to negotiate the world of publicity - impossible to know what will be effective. I've spent months or years of my life doing all the usual things writers do; giving talks, using social media, to no obvious effect. Will these stories have an effect on the sales of my novel? What exactly will the relationship be between nearly 2 million readers, and actual sales?
Watch this space.
I'll let you know.