No worries CArson, your advice did no harm.
I got it out without disconnecting the cable and without any other tools, the cluster came out pretty easily just by pulling at it with my hands and I unscrewed the speedo from inside.
I was looking to see if there was an obvious reason my tacho isn't working. I can't work out how the tacho works, there was no cable attached to it. Surely there must be a cable to it somewhere?