What have you done today with your Austin Seven

[Duncan Grimmond]

Not knowing the precise alloy being used can add to the problems. My experience has been that extruded aluminium is considerably harder than rolled and consequently needs more frequent annealing. As soon as more resistance is felt, stop and anneal again. I have found that extruded section seems to anneal better if quenched evenly in a bath rather than under a tap.
It makes the job more time consuming and difficult but making tools and jigs to hold and hit with, and form around always helps. Hardwood punches are very useful.
As ever, the rule of "more haste, less speed" applies. (Oh, and a big rubber mallet helps too!)