Quick update, with two weeks to go:
Swimming: I've got a strong, slow/medium speed front crawl, I'm too fast for the slow lane in the pool, but too slow for the fast lane. I've done 3 open water swimming sessions, with the 3rd being today, I did 1.2km. Sighting is getting better, and I think I'll be ok for the swim.
Bike: I've been doing plenty of rides, did 36 miles yesterday, and am confident the bike will be the strongest leg of the Tri. I won't push too hard though, to save a bit in my legs for the run.
Run: I've had problems. My 5km route is fine if I run slowly, but if I run strongly I get quite bad backache afterwards, and for the next 2 days. This sets me back for swimming and cycling. I had this before when training for a half marathon. Running on grass is much better and I can go faster.
With only 1 week of high intensity training left, I've decided to stick to short 4km runs at an easy pace. I know I can do the run, and have done several brick sessions, so the plan is to just accept I'll have a bad back for a couple of days after the event.
Not long now!