Spitfire distributor follow up

I have looked up the distributor in the Parts book and it certainly looks like the original part. I think I will order a new cap for it tomorrow to see if that fits better then the one thats on there at the moment. I have also noticed that the shaft that the rotor arm sits on has about 6mm of end play in it. I'm not sure if this is normal or not I am going to post a question on the Club Triumph forum tonight, if anyone has the answer it will be one of those guy's. Talking of Club Triumph I have just filled out my entry into the Historic counties rally taking place later this month. I have decided to take the TR4A as it is a bit more comfortable on a long run than the Spitfire. I don't know what to expect as this is the first time I have done one of these runs, I am looking forward to it though.