Clivewatson,
You've made an excellent point. The accel readout on the Falcon is quite useful. Unfortunately, Airbus hasn't got one like that. Maybe, somewhere in the inner workings of the MCDU, you can pull that up. I've never seen it, though.
The USAF method is pretty reliable, and I use a modified version of that.
It's unapproved, not SOP, probably illegal, but it also works well. That is,
as you pass the three-thousand foot marks, your speed should be at least
100 KIAS. Typically, it's 120 KIAS or thereabouts. But, if the 100 KIAS
callout occurs near or after the 3000 foot marks, you have a problem. I've used this in the Boeings and the Airbus. It works.
Now I am ready to have rocks thrown at me for this post....
Fly safe,
PantLoad