Dehumidifier or PIV or window vacuum or…(listed building)?

Mardle

Maybe consider a trickle extractor with a humidistat for the bathroom. It will run continuously and boost itself automatically when you have a bath or shower. 

We live in a large end terrace built in 1908 and have a trickle extractor in our downstairs wet room. It's very quiet and does a great job of keeping the humidity low throughout the house.

JJC1956

I’m no expert but someone suggested to me a couple of years ago to buy a De-Humidifier, I have to say it was money well spent, it is a Meaco 20L Model, the price seems to have shot up since I bought mine though.
If I am at home I put it on in the bedroom during the day and in the living room during the night, it is very quiet, my heating engineer told me he puts his washing next to his one as it dries it a lot quicker.
A 20L model will work in houses with up to 4 bedrooms, unless I have a spell of damp in 1 room, I leave all of the doors in the flat open, so that it works all around the flat, it really draws out the damp from the walls, if your place is quite damp, you will probably be emptying the water out almost daily, you will be surprised by how my water the machine draws out.
As someone else has already said you need to spray mould remover wherever appropriate.
My model can also be used as a fan in the summer, not that Ive tried it.

Chickereeeee

I wanted to retain our original wooden windows, which have leaded top lights. I opted for DIY  magnetically attached polycarbonate sheet secondary glazing for the leaded windows, and wooden replacement sashes with thin double glazing for the large panes. Brush draught excluder to all openers. Result is that the windows look exactly the same from the outside, but zero draughts or condensation and MUCH warmer.

edgex

1) Get the glazing sorted. You might be able to get it double-glazed, it's not just uPVC that's available. If not, decent secondary glazing, & deal with any gaps around existing frames.

2) If your going to replace the bathroom extractor, see if you could replace it with a MVHR one. They are able to recover a lot of the heat that you'd usually lose through an extractor, which means that you can run it for longer without an impact on the heating cost.

3) Make sure washing is really well spun before removing from machine. Put it on for another spin at the end of the cycle. Then try & dry it somewhere where you can leave a window open a bit, & not over a radiator heater!