It's been said that writing for TV is a series of compromises.
There are jammier shows, but throughout its successful five-season life, The Sarah Jane Adventures seems to have survived by this principle too.
We’ve had many stories in which a strong part one has been compromised by a much, much weaker part two. We've had clever endings that have been compromised by being preceded and followed by other stories with very similar endings. And pretty well every regular character has been compromised by being turned into a zombie, very rarely to remember afterwards how often.
This story however, even after completion, was always going be a series of compromises, for the very saddest of reasons. After all, just how is it supposed to be possible to watch The Man Who Never Was without compromising its achievements by dwelling throughout upon the lead actress' untimely death shortly after wrapping?
With that awful knowledge, I find it impossible to watch this one objectively, and yet, this final story is arguably The Sarah Jane Adventures' finest hour.
It's not the story that anyone would write as the series' finale. It doesn't feature the Trickster trying to change history so that the last five years never happened. Neither does Maria return to attend her mother's wedding. Nor do Clyde, Rani and Sky go their separate ways to university. Nor does it finish with Sarah turning down the fourth Doctor's offer of more travels in the TARDIS in favour of her new family on Earth. Heck, they don't even sit around the attic recalling clips. Nope, it's just business as usual.
Because it was.
As such, there's yet another zombie, who as per normal is treated as though such a concept has never been featured in this show before, and certainly not over a dozen times. There's a pantomime baddie who has no redeeming features at all, just in case we might find some excuse in his attitude to challenge our own selves. And there's also the machine that he's using, which has to be turned against him. Even BBC News gets in its usual report about the impending worldwide disaster.
However lest you think that SJA limped out with yet another half-hearted go at its exhausted regular formula, the series' consistently best author turned this telling into a doozy.
The characterisation throughout is as spot-on as it gets. The comedy actually has banter, which never lets up. The tale carries an educational message about the modern-day slave-trade, with the whole thing a satire on ipads and much computer hardware's alleged sweatshop origins.
Even the successful subversion of Harrison's control device isn't really what this conclusion is about. There's a tasklist of other challenges that our heroes have to successfully make happen too, against the odds of course.
And the direction. Quality, just, quality. It felt like a really good Doctor Who, and what more can we really ask than that?
There is no sense anywhere of these being the last two episodes ever, but they maintain a consistency of tone that so many others fail to, and are genuinely enjoyable.
Well, mostly. The way that hologram was operated was inspired lunacy, but when it went wrong I found the comedy trying too hard. Funny Toy Story line though. Shame the aliens never used their hypno ray on their master.
In terms of accidentally tying up the series' loose ends, it's an enormous relief that siblings Luke and Sky get to meet each other in this, and indeed gel together so well. Had the series concluded one story earlier, that introduction would have remained gallingly outstanding. Maybe the truncation of this planned final season didn't get away with quite as much damage as it could have.
And production-wise, that's the really big compromise - that we should have had three more probably dreadful stories after this about Sarah Jane and friends noisily defeating BBC News-heralded-zombies by switching their machine into reverse by just speaking the right sentence.
Instead we finished on a two part-story which I pretty well loved all of. Really, I did.
Except for, crushingly, the final 30 seconds. I feel sure that many saw this closing montage and were genuinely touched by it, but I felt it finished the show on a series of fumbles.
But you know what? I don't think my many problems with those 30 seconds are worth going into. It's good that they made the effort to draw a line under the series rather than leave it open-ended, and no-one wants to pan an obituary.
Tell you what I will point at though, and that's the final on-screen caption "And the story goes on... forever."
What the heck is that supposed to mean? Does Sarah continue saving Earth with Luke, Sky, Clyde, Rani and K-9? Or do the kids carry on without Sarah next year? Or does Sarah carry on without the kids next year? Does everyone get replaced? All of these possibilities are suddenly hinted at by that non-committal caption. For all the questions it raises, they might as well have just mysteriously flashed up "The end…?"
So, ignore that. Think of the series as finishing with Luke and his sister Sky hugging instead. There - everything worked out well for Sarah and the gang in the end.
What's that? A new BBC book containing the scripts for the remaining six unmade episodes?
No thanks. The Sarah Jane Adventures are complete.
And what a high to go out on.