I used to live in Cardiff. I used to live in Bute Park, come to think of it. In the Castle Mews. Once stabling for the Marquis of Bute's horses, some time over the last hundred years it was converted into sixteen flats for park workers. When I was there, fourteen of them were empty. The walls were solid stone, there was no heating. I learned the meaning of cold that winter.

But it was big on atmosphere. When night fell, it felt like I was alone in this cavernous stone building, in the middle of a large park. Who would hear screams? Certainly not Gerry and Gwen, in the only other occupied flat. They were in their seventies and deaf as posts.

So, when I needed a city park to set the opening, (very scary) scene in my fourth book, my thoughts naturally turned to Bute Park. True, it was over twenty years since I'd lived there but I could more or less remember it: the magnolia lawn, the fairy-tale elegance of the castle, the river Taff running through. Book four is all but done and last Friday was my final tick-all-the-boxes trip.

Now, they who must be obeyed without question (editor and editor's boss) have previously given me clear instructions that I need to broaden my commercial appeal and step away, a little, from the claustrophobic, bucolic settings of my previous three books. I need to become more contemporary.

I'm fine with that, honestly. I've enjoyed being the high priestess of English Rural Gothic but a girl has to cast off the purple mantle sometime. I was ready for something a bit more grown up - more serious - and I've enjoyed writing book four like no other.

So what do I find, at the exact spot where the "incident" in Bute Park has to take place? A bloody great stone circle!

Now, I swear it wasn't there when I lived here. Actually, it probably was but I swear I never noticed it. Or, if I did, I swear, it had gone completely from my mind. Whatever, it's there, and either I rethink half the novel or I bow to the inevitable, rewrite this scene in true Gothic fashion and send the purple mantle to the dry cleaners in readiness for a few more outings.

You can't fight fate!

We were deeply saddened last night, on the way back from Hampshire, to learn of the death of Dick Francis.  Husband (from a very horsey family) introduced me to him years ago and I've been a firm fan ever since. I've said this before, but it's worth repeating. Few writers can pen an opening line like Dick Francis.  Open any of his books and you'll see exactly what I mean.

I work very hard on my own opening lines, trying to make them as impactful as possible. I'll try even harder in future, and I'll do so in his honour.

Thanks for the stories, Dick. We'll miss you.

Absolutely nothing is the honest truth, because all I feel at these moments is a rather odd sense of loss.

For several months now, these characters have been with me for just about every waking moment. Their story has become another life for me, that I've lived in parallel with my own and now that it's told, I find them slipping away from me, getting fainter by the day, already little more than ghosts.

I miss them. I've learned to love them these past few months: Solvay, Mark and Dana (yes, she's back) and without their constant company I find myself strangely bereft. I imagine I'll feel like this when my son leaves home. 

The truth is, writing a novel never feels like hard work for me. It's the most enormous fun. The research and planning can be tough, although I rather enjoy it, and the editing process can be (and usually is) absolute torture, but the first draft is a pure joy. This one especially so. I've loved writing this book. And now the fun's over. 

My sister and I are planning the official launch of Blood Harvest, due out in just over two months. As the book is set in my home county of Lancashire, and based on the real life story of when my sister and her family built a big new house on the moors by an old church, we've decided the launch will be in the north. This does mean inviting people I haven't seen in twenty years. Scary thought. If they look old, does that mean I do too? Are they going to come armed with endless embarrassing stories? Will there be photographs? Maybe it's not such a good idea.  Too late to back out, though, my sister's  bought a new frock.