many thanks in advance [and yes there is one somewhere as you couldn't build it without one ;-)]
an offline "dpkg --list" was what i was looking for to find that BT4 has "magicrescue" which it does thanks.
Two things. One do as you suggested in your second post. (dpkg --list) or two follow the links that were given.
I would suggest taking a close look at second aforementioned link. There is a definite answer in the thread.