I had a look at the springs today and sure enough they are both broken at the bottom on the smallest coil, about 2-3 inches of spring has snapped off. The passenger side was a clean break and the small part was loose so I removed it without any force.
It looks like they have been broken for a while, there is too much corrosion at the break point for it to be recent, yet they hadn't been noticed on previous services or MOTs. That said on initial inspection I couldn't see the breaks and it was only because I was looking for them that I saw them, otherwise they were easy to miss.
The breaks might explain the intermittent creaks that have come from the front of the car since I've had it.