It seems that SHA is searching for a new name, believing that its current title no longer reflects the fact that deputes and assistant heads outnumber member heads, while increasing numbers of college leaders are joining.
The simplest solution would be to opt for Secondary Leaders Association, but SLA is not too inspiring and it does not include colleges. A snappier acronym would emerge from Association of College and School Leaders, pronounced Axle. Driving change and all that.
As for the HAS, the Association of Scottish School Leaders might have unfortunate connotations if pronounced too quickly.