niknak - sorry, too deep for me! Unless you want the CAA to tell you what to when it's dark?
Findo, I take the TCAS climb call as the start of a manoeuvre over which I have little control. It hasn't happened to me often but it usually seems clear when the event is over and everything is back to normal. In the interim, I'll tell any other aircraft that might be affected about traffic coming their way. If it looks like a good idea I'll give a turn to the climbing traffic but I won't be surprised if the aircraft doesn't do it.
In many ways, a lot depends on the airspace you're working in. If it's Class A a TCAS RA probably means that something has gone wrong and not been picked up by the controller or any other alert system - if there are any. In Class G, which I am more familiar with, there can be any number of quite legitimate circumstances that trigger an RA. Some are adrenalin-filled, others are just part of the fun of Class G. But I think the two environments are very different as are the ways that a controller might respond to them.
Not a perfect answer - but not a perfect situation. I'm aware that issuing avoiding action in the vertical is not be a good idea when TCAS RAs are involved and I'll avoid doing so. But if in the circumstances it may resolve a conflict I'm glad it's available. A controller who doesn't want to issue vertical avoiding action has the perfect excuse for not doing so - but every controller is different as is every conflict.