Redwater: Overheated, overcooked, and why are they over here?

Just when you thought it was safe to get back in to Redwater (RTÉ One, Sunday, 9.30pm), the EastEnders spin-off set in an Irish seaside town, along comes an episode heaving with crashes, smashes and splashes.

It is not all that surprising that two car accidents, a number of shattered drinking vessels and a couple of ceremonial wettings should revolve around another celebration, because the town of Redwater abounds with the things.

This series introduced Kat and Alfie (Jessie Wallace and Shane Richie) to the heedless abandon of spring equinox (an Irish festivity unique to this fictitious Waterford hamlet). Soon after, it solemnly repaired to a song-filled wake for great grandfather Lance Byrne ("Double G" to his youngest descendants, but, thanks to his murderous grandson, Fr Dermot, now tragically made "Zero G").

Since then we’ve had a barbecue memorial, ridden with weird rituals, for the tragic events of 1994, which was a double drowning whose details are still misty. Now, with the arrival of Andy and Bernie’s baby, we get a christening so fraught with family tensions it is a miracle that no one else dies.

But, since the numerous upheavals of the show's introduction, writer Mathew Barry has preferred more modest blow-ups to bombshells. Here, there is a wonderful shot, during an ostensibly comic subplot to rescue a christening cake from a grieving widow, when the car conveying star-crossed cousins Andy and Kieren careens violently off the road into a ditch, and Peter Campion and Ian Toner share a stunned, wordless moment. They are an easy adulterous, incestuous couple to root for.

Still, in this penultimate episode, mysteries persist. Chief among them is what EastEnders Kat and Alfie are still doing here. For a show that, in some versions of the title, bears their name, the couple actually get comparatively little screen time, as though Barry accepted early that they were his least interesting characters.

Seeking her long-lost son, Kat was initially a clumsy investigator digging into a guarded community, while Alfie, living with a brain tumour and troubled by visions, was her permanently glum accomplice. Now, with most of that secret solved, they’ve become more like an audience.

What they are watching, as Redwater laps towards its conclusion, is a very knotty, overheated family drama containing a very meagre, undercooked detective show. Having sent her daughter's smart phone away for forensic analysis (if you know of any easier way to enlarge a single photo, the writers want to hear it), Garda Bernie finally receives a blown-up image of footprints leading away from the scene of Lance's death. It can only be a matter of time before she realises they are priest-shaped.

Meanwhile, sibling rivalries flare, cousinly passions ignite, parents are bitterly denounced by their religiously-demented changelings, absolutely everyone complains about everyone else’s drinking, car-crash cakes are salvaged and Bluetooth devices come out particularly badly from the whole thing. Typical family stuff, really.

All the performances are creditable, particularly Fionnula Flanagan as the impeccably dressed and immensely icy great grandmother, Agnes, who alters between being casually disparaging or stridently demonic. (This week we learned that she is a Daniel O'Donnell fan. Make of that what you will.)

But no performance is quite as good as that of Dunmore East, playing Redwater, which alters between being sunnily alluring, or a blue-grey tangle of brooding secrets. Their story has run its course, but you can see why Kat and Alfie still want to hang around.