You have better luck with a older cam cover like from 05, 06 , 07, for sure. Im not sure about when Triumph changed the covers maybe Roadster time frame ? I only have 05 thru 07 so I can definetly say they are the same. I'm not saying you can't get the newer ones to seal they are just more particular. You can see the difference below first older style
Now newer style
Thats probably why the older bikes don't have the oil leaks as often.