I've read a few comments by people regarding the need to "train" the ISC to work according to your driving style, and am wondering if that might explain recent problems I had with mine.

The other week I had my TS in to get the timing belt and other parts replaced, during which time the battery was disconnected. On getting the car back, at first I found it to be exhibiting behaviour consistent with a faulty ISC, to the point that on a couple of occasions it actually stalled. I had previously thought it might possibly be a little dodgy, and took that as confirmation.

However, it now seems to be working just fine, and I'm wondering if maybe it just needed to be "trained" again following the disconnection of the battery, and that it was in fact fine all along. Does this seem reasonable to others? Unless the ISC is just failing intermittently, I'm not sure what other explanations may fit. I do have a new ISC to put in if needed, but at the same time don't like doing jobs that aren't required.

Any suggestions/advice much appreciated!

No, that sounds reasonably correct. They do it sometimes. All thats required is a bit of a drive for the ecu to relearn its values again.

I have the TS V6, and on the occasions when the battery has been disconnected by either my mechanic or the NRMA replacing a battery, they would go through the procedure of turning different accessories on. They would make sure that all accessories were turned off. After starting the engine, they would turn the heater fan onto full, turn the AC on, followed by the headlights, brake pedal lights, turning each accessorie on after a short delay. Never had a problem driving the car after that.

Ozz

PS., another possible issue you can look into is that of leaking capacitors in the ECU. Apparently they are getting to an age where it is a known problem, the capacitors leak electrolyte over the board which shorts stuff out, initially giving intermittent faults.

Doesn't really sound like that, but thought I'd raise the issue so you are aware of it. Just requires the lid to be taken off the ECU and a visual inspection should tell you whether they are still good. I haven't done this personally, so don't know exactly how easy or hard it is to do (a mechanic inspected mine a couple of years ago when I had my ISC replaced, said they were still good. But might be a good idea to do a checkup ocassionally...)
Replacing about $1 worth of caps in time can save you a good $150+ worth of ECU. But you'd only do it if they were showing signs of trouble.