Only peripherally to do with DIY, I'm afraid...
Last year I had a loft conversion done on my bungalow: it was a long and messy job and I moved out for nearly six months. I decided to remove the property from the valuation register to avoid paying council tax while I wasn't living there.
The property went back on the register in January, and naturally I started paying tax again. Now, I've just received notification that the banding has been increased from C to D - removing the bungalow from the register apparently allows them to revalue it when it goes back on.
If I'd realised that, I would have continued paying at the old rate while the work was being done. Saving six months worth of council tax will cost me several thousand pounds in the future.
Which is annoying.