replacing interior door architrave

[wr1ght]

Hi
i am replacing the architrave on one of my internal doors, on removing the old architrave it has a groove cut into the back where it slots into the door frame, the new architrave does not have this groove so what would be the best thing to do either pack the wall out (this may bring it out too much) or cut the piece on the door frame back (worried once i have cut it no going back)
any advice please

 

[foxhole]

Photo too close no perspective.

 

[wr1ght]

thanks for looking

 

[Dazza Jones]

I had this before and I just cut the piece off as it was easier than cutting a groove into the new arcitrave.

 

[wr1ght]

thanks think this will be the best option!