Isolation valve on boxed in pipes

[Coaster]

I've discovered an isolation valve that was left in by a plumber from an alteration to bathroom pipes.
I have been advised on another post that isolation valves can be a bit dodgy. Should I take it out incase it starts leaking away while being hidden?

 

[Burnerman]

I'd leave well alone - they are usually fine until they are turned - after that its worth keeping an eye on them for a while.
Some of the cheaper ones actually leak from new....which is a complete bind!
I'm talking about the brass ones, by the way.
John