With a little DIY skill, it is possible to adapt say Petzl accessories to eg DMM axes and vica versa and so change your older Scottish mixed tools into continental style leashless climbing axes. Here is a chart of what we feel works in this respect - if you have successfully made an adaptation not listed please let us know and we'll add it. It should be noted that any adapting of parts to fit axes other than those they were intended for will almost certainly invalidate any manufacturer's warranty that comes with those parts.
We should add in a note here about the latest Petzl Trigrests (both sorts). These are very easy to fit to nearly any axe and the trig bit can be discarded leaving just a bolt on rest, which is what most people want. It may be necessary to remove some of the rubber grip from your axe to get them to fit. However, they don't give much hand protection when fitted as a lower rest and we have had reports of breakages.
Handrests: Handrests (also known as Griprests, Fangs, Horns etc) are the hand-resting/protecting hooks that are designed to be fitted to the bottom of the shaft of icefall axes. Although they are only made to fit certain axes, there are plenty of botch up jobs out there where people have fitted them to axes such as the DMM Fly - check out the UK Climbing Gear and Winter Forums for examples of how to do this.
Shaft Rests & Triggers: Shaft Rests are small rests fitted about halfway down the shaft to enable easy hand changes when climbing leashless. They are also quite useful when climbing leashed as they enable the axe to be gripped differently. Triggers are intended to be fixed to the shaft of your axes in such a position that your index finger rests on them and gives great control and accuracy.
Axe Grip: Rubber or other material to make axe heads and shafts easier to grip.
Headweights: Extra weight that can be fixed to the head of an axe to increase its penetration into hard ice.