I don't think either of us are going to better our 100 times, where he has 6:08 advantage on me. To beat him, I'd need to equal his time (a short 1:54) in the 50 and make up for the 100 in the 12. I reckon I can pull back the 50 time on a good day, so that would require a 12 hour ride of [goes off and fiddles with a spreadsheet] 269.76 miles. It also requires him to not do another fast 50. This would require me to set a demanding schedule in the 12 and risk blowing, rather than ride a more conservative schedule to take the club record from him. Another issue is that the 50s I can do (the Yorkshire and the Breckland) are two and three weeks after the 12, so I'll have to see how recovered my legs are by then. The Breckland would probably be a safer bet (and extra week's recovery plus probably a faster course) but as you say it's a trek, plus I want to be doing other things with my life by then. Hmmm, it's something to ponder.