Front Propshaft Bolts....

I have to replace the front propshaft and bolts.

Will have to cut the bolts off as the nuts are not moving (no matter what I do). But befor I start cutting. I'm working out how I can fit the new bolts.
I understand that I have to remove the Flange from the transfer box.

But the I'm wondering what is the LIP that runs around the FLANGE that stops the bolts form coming out?
And how do you get it off?
Will I need a new one once its off?

Thanks

Marky

its easier to cut nuts off with chisel hitting on flat with chisel top tp bottom of nut it will split it once flange off (30 mm socket) pull flange off and if you whack down on a piece of wood with bolt ends they will push mud sheild off will refit