Thanks for the suggestions so far.
I do have a replacement indicator switch, but when I unplugged the old and plugged in the new off the car it didn't make any difference, but that might have been earthing, I was just trying to see if it worked before pulling everything apart.
I'll fiddle around again and report back. I have discovered in this process that I'm not as bendy as I once was. Mrs Druid was clearly right all along.