I'm no mechanic but the shimano website says the nexus 8 speed is 132 over locknut. Seems like I heard that it means it will fit between 130 0r 135 dropout. Maybe Rev Chuck can verify. According to website all 8 speeds are 36 hole. Do you plan on keeping your front derailleur? If you plan on using just one chainring pay attention to chainline, needs to be pretty straight. Might be easier to sell the sirus and buy a bike with a gearhub already in it. There should be a lot of them on your side of the pond. Unlike here in the US where they are somewhat scarce. Best frame for a gearhub is one with horizonal dropouts or an essentric bottom bracket if using vertical drops.