Trigs and a Trig Lookalike

Decided we needed to bag some trig pillars today. Well, I did and the girls were dragged out on the promise of lunch out if we found 3.

Well we did. And we didn't.

First off is our nearest trig pillar which I'd never hunted before - it's on a railway embankment so we had to view from the bridge.

Then we went to find the trig on Constitutional Hill.

Here it is!

I was surprised there was no evidence of a spider or FB but I assumed this was a cheap and nasty OS version.

On returning I read the details properly and, lo-and-behold, there is the real trig pillar 100m further up the trail. Doh. What I want to know is why are there two trigs 100m apart from each other - one the official one and the other a poor cousin. It's exactly the same shape as an OS trig pillar and fooled me (no comments please). I wonder if the OS installed this one and then changed their minds for a slightly better location? Can anyone enlighten me?

Lastly, a real trig. This one involved a tramp across very gloopy mud but the views were worth it.