On Friday, 22 September 2017 11:53:31 UTC+1, David wrote:
Mask wall, floor, cat etc up with newspaper and tape

Good luck with cat :-)

Spray it with radiator paint
Hey, done!
Now this looks pretty easy, which makes me worried.
Any top tips for painting them in situ?

Unless you can persuade aerosolised paint to bend round corners you will only be able to spray what's in line-of-sight of the spray nozzle.

You may need an extension nozzle on a very slim tube to be able to spray from 'inside' the columns.

Owain