Bathroom condensation

[MrsRussell]

Downstairs wet room and toilet, quarry tiles on walls and floor.
The radiator started leaking in November and we disconnected it (plumber is coming mid January: it's the earliest he could do and he's the plumber we usually use) so no heat source since then.

The wall tiles are wet to about 8" up. There's condensation dripping off the cistern and the bottom of the U-bend, the back of the cold radiator, and there's moisture (not water) spreading across the tiles.
Moisture meter running about 76% currently (it's an old granite cottage) - ambient temperature in the rest of the house is 20 degrees but back there it's about 13 due to two external walls.

Is it worth me running a dehumidifier for a couple of hours a day, just to keep the moisture down till we get a heat source in there again?
Window is open but it is like an ice box in there... am I just stuck with it till January?

haven't you got an extractor fan?

We have not @PigletInABlanketJohn, sadly.
It's not a room we use as a wet room - it's tiled as one but we only really use it as a downstairs toilet. We go old school for that and open the window...
Left the window open last night and it's slightly better in there this morning but there's still masses of condensation on everything.
It's so unseasonably warm here! Heating has gone off an hour ago and it's still 19 degrees!

I recommend you look into getting an extractor.

If you decide to use a dehumidifier, keep the door and window shut.

It will also add some heat to the room.

First priority is getting the radiator replaced but yes. (It's one of those old houses where the owner had basically bodged every single thing that could be bodged over a period of about 60 years, so we're still finding weird little quirks like the inexplicable hooks in the kitchen....)

I cannot imagine why you would even want to shower in a tiled outhouse like something out of the Beverley Hillbillies - it's basically an old-fashioned scullery that someone's hitched a shower up in. It's BITTER in there. We put shelves up and use it as a larder, that's how cold it is.