Why do I love DIY SOS? I don't do bad DIY. I don't do any sort of DIY. Occasionally, I think I might, but then the urge passes. Still, I love DIY SOS.

It could be because of my faintly embarrassing thing for Nick Knowles, but I think mostly it's because it's highly entertaining. Or at least, it usually is.

Last night's episode was the first of a new series - the 15th, if you can believe that - and not only has Bob gone, but they've got a new, posh designer called Clare, which is kind of a shame because the rows with the last designer, Debs, were some of the most entertaining bits. There was a weird conceit that, following the last series, they'd all been banished to Albania and Debs was still there herding goats, but that's best ignored.

Bob's been replaced by the cute little Irish fella who used to be in the extra bits with Lowri Turner (also gone). Plus the recipients of the makeovers used to be chosen by the viewers and, of course, following all the phone-in scandals, that's out too. They're not the only changes, they've got a 3-D design illustration that put me in mind of the old Paddington cartoons. Thankfully, Billy the hapless electrician remains.

So they were in Southampton to help Paul, Sarah and their daughter Caitlin. Not long after buying their house, Paul suffered kidney failure and got a transplant from his wife, meaning, um, they haven't been able to decorate their living room. And probably some other stuff too, but it wasn't really addressed here.

You don't get many DIY tips with DIY SOS - although Chris did say it's possible to plaster over Artex, which lots of people say you can't - and there's barely any footage of them doing any work. The main point of the show is the relationship and banter between the builders (and Knowles).

The jokes are poor. The innuendo is about the standard you'd expect from builders. But, like Tim Vine, they wear you down the more you watch. (And though the standard was particularly feeble in this episode, there was one smutty gag that made me yelp with laughter.) Plus Nick Knowles has got TB, you know, leading the builders to get fetched up in Hazmat suits. Ho ho.

As with so many TV shows these days there's an arbitrary deadline - "We've only got 4 days to get this done." Um. Why, exactly? It's also not true. Opening a box of flatpack furniture, Knowles read that it took three hours to put together. "And we've only got 15 minutes left," he grimaced to much laughter. And yet they managed it. That's teamwork!

One thing about DIY SOS is they do tend to do the work for deserving people and, following a check up at the renal clinic (no, really) the family cried while talking about how much of a difference the room would make to their lives.

Since I've been working from home I've watched about 50 episodes of DIY SOS on UKTV Style (between working, not instead of working, obviously), and I have to say, with a heavy heart, this one wasn't up to scratch. Something was missing. A spark (and I don't mean Billy). They team just didn't quite gel. Could just be teething troubles as the new team get to know each other, could be Nick Knowles adjusting to having an infectious disease. Whatever it is, I hope they get over it soon, because I used to love DIY SOS.

DIY SOS: BBC1, Friday 20 July, 8.30pm