Brillliant. Thanks very much everyone. I'll book something now.
It's a busy period at work for the next few weeks, and if I've got a stiff neck and shoulders now it'll only get worse as I spend more time hunched over a computer, so I reckon I'm entitled (nay, obliged) to treat myself to some essential therapy.
I've got to admit that my curmudgeonly old man side comes to the fore ( "Is it ever otherwise?" you may ask) when thinking about flotation tanks.
I know nothing about them, but somehow I feel distrustful of them ("distrustful" in a snake oil way, not a fear and loathing way). I realise this isn't exactly a testament to my liberality of thought, and you seem to be impressed by them, so maybe I should give it a go. I can see that weightlessness could be good for stiff backs etc, but I'd be more drawn to having a massage because it seems like an active solution, where floating seems passive.