Morris Minor Owners Club

I did exactly the same a roger,drilled a small hole just under the clips ,simple job to get the clips free.One bit of advice,don,t take the headliner off the front board before you have very acurately measured the distance from the edge to the back of the old headlining so that you can fit the new one in the right position on the board ,the new ones are all slightly different in length,its essential that you get the seams(Wher the rods fit) in the right place or when you tension the wires it pulls the cloth out of place and looks a mess(Been there ,never again)

Drawn a line on the board where the old material came to and use it as a guide to place the new to.

thats what I did on the first fitting but then discovered that the new one was longer,and needed to be further on to the board so back out and then a fiddle to get it right It was about two inches longer not just a little bit .The distances between the seams were ok just more material at the front.