TL;DR: I cruised 3:51:46.
You might ask: "if you cruised that, why not try a bit harder and do a bit better?" Which is a fair question. the answer is that I hadn't done any significant long distance training since Amsterdam last Autumn; only the Folksworth 15 and a 24k along the river. So I really just wanted to get under 4 hours again, which I'd failed at in Amsterdam by a whisker. And I didn't want to spoil that by running too fast and then blowing up. Arguably that only applied to the first, say, 3/4 of the race giving me no good excuse for the last 10 k. But meh; it was going well, I know my habit of falling off a cliff at the end, I'm happy.
Here's my full set of results, for reference.
Brighton 2011: 4:20:29
Rotterdam 2016: 4:16:51
Amsterdam 2016: 4:00:08
Amsterdam 2014: 3:58:00
Amsterdam 2011: 3:57:23
Rotterdam 2015: 3:55:54
Amsterdam 2012: 3:55:52
Brighton 2012: 3:54:28
Manchester 2017: 3:51:46
Brighton 2013: 3:46:32
Brighton 2014: 3:43:42
Amsterdam 2013: 3:43:06
So this is my best result since early 2014; and my fourth best of 12. I think that reflects my general fitness declining somewhat since the "great year" of 2013; largely due to pressure of work.
Of the run: the race makes the very sensible decision to have wide (2-road-lane) start area pens, which is then constricted down to about 10 feet wide briefly just before the start on a right-angle turn, before widening out onto the actual start line. Which means that you can run, unrestricted, right from the start. Excellent. They're also quite unfussy (read: I saw no marshalls) about exactly which pen you go into (which makes sense really: there are no constraints on what time you promise beforehand). So since it was convenient, I started just in the gap between C and D, just a little ahead of the 3:45 pacers. That lead to a steady stream of people overtaking me, but not too fast, so it was fine. I held the pacer off till 30 k, which was fine, as (since they started let-us-say 1 minute after me) that gave me ~14 minutes in hand over the last 12 km.
The first 21 km were fine; I started at 5:10 and faded according to plan to 5:20, and so got 1:50 for the first half, giving me a comfortable cushion for the second half. But! I've been there before and lost all that comfort, so I was more careful. One expression of that care was stopping for a pitstop at 25 k, mostly because I needed it, but partly to take off whatever time it would take early, so I could factor it in. As it was I managed a high-quality Formula-1 style 50 second stop. At that point my fade hadn't really kicked in, so I got 6:14 for that lap, and hardly lost any of my notional cushion.
Things started to slow a bit at 30 k, where my splits dropped from 5:20 to 5:40 and stayed there; then dropped to 6 at 35 and stayed there; but by 39 k I started to feel a bit ashamed of cruising quite so easily, and speeded up a little. Vignette from 2k out: man on bicycle cycling next to his son: "come on now, you're nearly there, and you're over the worst bit". Son: "No. I can assure you that this is the worst bit". For me, about 7-8-9 k out was the worst: still a ways for the line, and beginning to get tired.
One nice feature of the route is that between 14 k and 22 k the outward and returning streams are on two sides of a normal road; so you get to see the leaders coming back; and somewhat later I cheered on James as he went by. To my surprise the leading pack were all white; which will be why it was won in 2:20 rather than 2:08 or somesuch.
By happy chance I met Elissa Tennant-Brown at the start; she said, tentatively, "did you row the Boston marathon a few years back?" And indeed, yes, I had, when she was our cox. I also met her at 32 k when she ran past me; and then said hello past the finish. She got 3:44, 7 minutes better than me, probably accounted for by sticking to her 5:20 while I dropped half a minute or more per k over the last 10 k.
Of the arrangements: I had intended to B+B an hour south of Manchester, and drive to there and then from there. But quite late James turned out to have a spare bed so I slept with him; and this enabled me to take take the train. Less hassle than driving if somewhat more expensive. Cambridge to Manchester is not especially easy, and in some ways getting to Rotterdam is easier. The Holiday Inn in the MediaCity part of Manchester (well, Salford officially) is achingly clean, and there was a pasta place nearby that James had thoughtfully booked. And walking from the main station took only a bit more than an hour, all pleasantly along the canals. If I was going to do it again I'd probably turn up earlier and give myself some time to look around; on a pleasant weather weekend as this was it's a nice place, and a coffee along the canals would have been relaxing. And there's always the matchsticks to look at.