I'm coming back on this thread after months where i have been off.
Thanks Till for the advice.
However, this has no effect.
If i am searching after having empty the recycle bin, i still find the website (though it is not available in the left tree menu)
Also, the recycle bin is empty in any case.
Should i do sql statements in the ISP config tables to try to delete the records related to this site that i want to delete ?