Don Johnstone wrote:

Which approach do you think a glider manufacturer test
pilot takes. Prove that the glider complies with the
requirements or test right to the limits. The latter
is the way that military aircraft are tested at great
expense, do you honestly think that glider manufacturers
can go to that expense.

JAR-22 certification requires exactly this.

What is a safe abandonment height, that is another
question. I know what I think mine is. Do you know
what yours is?

If you'd read my previous posts, you'd have seen that I wrote I'd never
start a deliberate spin below 3000 ft AGL, nor would I explore stalls
and control abuse in an unknown glider below this altitude. (This was
the post Ian replied to.) I consider this quite conservative.

Stefan