Thanks for your comments.
The point about the pop-up-or-out-from-behind-a-hill fast jet, which we are unlikely to see in time on receipt of a TA, is a good enough reason for keeping TA/RA always on, I now think.
A TCAS climb is unlikely to be a problem for ATC in the open FIR, as we are not likely to be conflicting with their traffic - in fact, we often can't get any service from Scottish at all on the west coast.
For Daysleeper: the "climb" RA may indeed lead to a GPWS type emergency climb - if the RA climb leads us up into IMC while below MSA. This was my main concern initially, regarding TA/RA while VFR.
However, I accept that the initial RA manouevre is not necessarily violent - probably considerably less than avoidance action on a flock of geese or a late visual acquisition of an aircraft, for example.
I gather you need to be really pretty close to a pop up aircraft for an RA to occur without prior TA. If so, the incidence of unnecessary RAs should be pretty slight.
We are, as suggested, using the Eurocontrol Bulletins for training purposes.
Finally, I don't want anyone getting the impression that we spend our time swanning around low level VFR. However, there are occasions when, on balance, we feel there are safety benefits from staying VFR (and being able to see the hazards, such as terrain), rather than being up in the bumpy, icy, clouds, looking for the, procedural, non-precision way down.