I agree with Pete and Lit, especially the "Horse for Course" bit. Perosnally, whenever I've tried a negative split I've bombed, and that is the same from 5k to marathon. All my PBs (mediocre as they are mind!) have come where I've raced feeling a similar effort throughout - ie getting slightly slower.
I tried cutting down on alcohol for 2017 - it only lasted one day unfortunately!
Good weekend of racing there Philip, especially throwing in an unexpected XC!
SG - the usual LSR is a 14, but almost the same route. I don't think there's "healing magic" in off-road (that only comes from running on the fells ) but it generally and genuinely feels less punishing, probably as a result of the softer surfaces, mixing up stride and pace more and generally not feeling the need to push as hard as on the road. Certainly, for me, any recurrent injuries seem to be more exacerbated on a long road run than an easy off-roader. Effort wise, I'd say 15 off-road is probably equivalent to 17-18 on-road, but that depends on hills, mud etc. Either way, it usually makes for a more pleasant run!
Still slow enough Ric, just came out quicker than the last few times without having to push it . In fact, its my first long run for ages where I felt I'd have been happy to add on a couple of miles (blister aside that is!)