The Madame Blanc Mysteries' Sally Lindsay teases season 4

"We actually stayed in the hotel where we filmed that episode the year before, and the whole episode came about because very unusually, me, Steve [Edge, who plays Jean's boyfriend Dom Hayes], Robin [Askwith, who plays Jeremy Lloyd James] and Sue [Holderness, who plays Judith Lloyd James] all had a day off together, and Sue and Robin decided to go jet-skiing, like normal 70-odd year olds do! They both loved it, and I got a picture of them, so when I got home and started to write the next series, I thought 'right, they're going jet-skiing' — I didn't know yet what the plot was, I just wanted them on jet skis, looking hot! That's really them doing it by the way, it's not a stunt couple. They spent all day shooting that, and they are brilliant. I just loved the idea of two absolute hotties in their 70s in hotpants, speeding across the Mediterranean. The whole episode is about that scene, and I thought, 'I've got to make a story up now!' And what I found out is that you cannot go past a certain point with a jet ski because they turn themselves off, so I thought, 'that's where the body is, isn't it?' and I worked back from there."

"Oh my God, I can't even tell you! It's really interesting — I'm not saying it's a bottomless pit, and I'm sure one day I'll run out of ideas, but I just haven't. It's like a parallel world, it's a bit like when I was in Coronation Street, you just step into that world and it's completely real. It's very similar: this is a completely real world to me, I know what's around the corner, I know the geography of it — it's all very real in my head. The tricky bit is, 'have we done this before?' Me and Sue are really harsh on ourselves about that — if there's even a sliver of something we've done before, we reject it and go 'no, think harder'. But there's only so many ways you can kill someone — look at my dodgy browsing history! But yes, if they still want me to make it and I've got the ideas, you just keep regenerating, which is great."

"It's great, because you don't really see middle-aged love stories, do you? Once you get to 50, everybody's like a dad or a mum, and they've got teenage kids — you don't see the excitement of new love in somebody of that age, so yeah, we're having lots of fun doing it. Steve's a massive mate of mine — I've known him longer than my actual husband! He's just brilliant, I love him to death, so it's very easy to do those scenes with him."

"Yes, because the thing about middle-aged relationships is that they don't owe each other anything, they've got nothing to prove. They don't need to move in with each other, they don't want children, they don't particularly want to get married — nothing's of an urgency, they're absolutely free to do what they want and I think that's fun. But that freedom sometimes has its problems, because sometimes you're not trying hard enough, or you think the wrong thing of someone, or you overthink things..."

"Richard's brilliant — I met him on a panel show! We shared a train journey back and I said, 'do you want to be in my show? It won't be like anything you've played before', and he said 'yeah!'. He plays this camp TV presenter, he absolutely smashed it. And Charlie's fantastic, I've known Charlie for about 20 years and I've wanted him in it for ages. His dad's French, so I wrote loads of French in it for him, and he went, 'I'm really bad at speaking it!'. But then he said, 'don't worry, I'll just sort it out with my dad' — he's really sweet like that, and he's absolutely brilliant in it. There are some real corkers in it this year — it's really nice when you can attract that kind of talent, and they come out and have a lovely time."

"Usually, even if the next one's not commissioned, we start writing it! We'll have a week off, me and Sue, but we do start again pretty much straight away. The last series usually informs the next one, and the world is naturally carrying on in your head, so it's always good to strike while the iron's hot, really! But yes, I'm shattered — it takes me about a week to get back to normal when I come home because it's knackering, but it's brilliant and I love it!"