My company SOPs on the A340 are thrust reduction at 1500'. The acc alt depends on a/c weight, obviously, but 1500' is the default. We use 3000' to acc. if we are not going to make the noise limits due to a/c weight, high ambient temp or significant turns in the SID. I was under the impression that this was the ICAO procedure - we use it at all our destinations, including Heathrow.
Don't get too intimidated by the wording of the NAP, as you say it's actually a "pilot-unfriendly" regulation, rather than a practical procedure for use in the cockpit. Also, the only time I've rung the bells has been due to lateral displacement on the SID, rather than a mistake in the vertical profile. The 340 FMGS often doesn't seem to be accurate enough to fly the lateral profile to what I consider to be acceptable limits eg if a turn is supposed to start at 5DME it often seems to start 0.2 or 0.3nm later and it seems to be this that rings the bells.
Hope this helps.