Which Half Ironman?

Radojadoj

Hi there, I have just completed my first triathlon. It was an Olympic distance and so thoroughly enjoyed that I'm now considering pushing myself further and doing a half ironman next summer.

My question is, which would be the best to complete on my first go, without putting me off for good? I live in London so UK would be ideal. I am strongest in the cycle although wouldn't want anything with never ending steep slopes. The swim I will be able to finish with some practice but my biggest concern is the run. I'm better at flat courses where I can keep consistent throughout and maintain a steady pace. 

So essentially looking for an interesting course to do in the UK that has some good scenery and a flat run course.

Any advice?