Hi Declan,
I bought the Flying Scotsman one when it was released and have had endless fun with it.
The smell alone is a joy but on a long open track it is amazing.
Only problem I had was when I put it away in storage for a while.
Not realizing it at first, I put in a box with padding, but the loco was lying on its side.
In doing this the valve became blocked by some old oil (you can never totally empty it).
Therefore I recommend that it is always stored standing upright.
Other than that no worries at all.
I hope you get as much fun from yours as I have from mine.