Thanks for all the good luck messages everyone; I'm not going to try and list you all in case I miss someone! But it's appreciated.
Anyway, I finished...
I cycled there in the morning (about 5 miles) so a nice warm up, went and registered and then had the first challenge; apparently marker pen is old hat for numbers and now its race tattoos - which took a good 10 mins to figure out how to apply. What I didn't realise is that if you aren't nicely hairless then trying to remove the things is just a way of epilating yourself one hair at a time (ow!!)
It turns out either I had my best swim by minutes or my eyesight has been letting me down and I've been completely misreading the clock in the pool when timing myself. Either way, I started in the 11 min group as the first one off in my lane (other 3 following at 10 second intervals), I figured I might have been a bit off with my swim time when I finished the first length first by quite a margin and was sure I'd got the time badly wrong when I'd lapped everyone else in my lane and left the pool 2 minutes before anyone else...
Transition 1 went kind of ok apart from the hopping around with a bright orange cycling top wedged over my head - I'm guessing I looked like a giant orange lollipop...
The cycling was good; I managed to take the 'new' bike out a couple of times on Saturday and felt confident enough on it to use it in the race - it was very fast, particularly into the headwind I only got overtaken once (twice actually but by the same guy) and averaged 19 mph over the 15 miles.
Transition 2 went much more smoothly, a complete lack of bouncing lollipop incidents.
And the bit you're all waiting for :) the run... The good; I made it, comfortably, without any pain in my shins and in an OK time. The bad; I could have gone faster, my pacing was very poor and I definitely had reserves 'in the tank' at the end... The ugly; stairs!! Some sadist made it cross a railway line and a dual carriageway twice! So FOUR flights of stairs which I hadn't trained for!
So the result (provisional) 168th out of 430, Swim 400m - 8m 46s, T1 - 2m 51s, Cycle 15.09 miles - 46m 35s, T2 - 1m 11s, Run 3.9 miles (6.2km) - 32m 35s, Total 1 hr 32m 01s!
So I think that means I've sort of completed couch to 5k; although I kind of missed week 8, I think.
Anyway, the next one is Buxton in July and I definitely think I could improve my times, I can't believe I couldn't run 8 weeks ago!
And just for continuity I'm afraid I didn't see any cows at any point round the course, but I did see lots of sheep - I don't think I caused any of them to hurl themselves startled into any ditches though.