You Can Have Only One Steam Locomotive In Scotland - Which?

[scottmitchell74]

So, the Union Mills discussions have got me wondering:

I only need (need  ) one steam for my purposes. The old concerns about N Gauge steam is what drove me to Union Mills in 2014.

But, the threads of late seem to suggest the modern steam offerings have come a long way.

What one steam locomotive that could have reasonably been seen in South Lanarkshire should I target?

I'm talking strictly model performance and reliability.  Looks be damned; I want a runner!