Converting window with stone surround into door

[New Horizon]

I am looking to convert my window into a doorway. The width of the doorway is to be the same as the window so I was hoping to not have to change anything structurally.

Currently, the window is supported by a stone surround (house is stone built externally) which includes a stone head, stone jamps and stone sill a bit like the image below.

I was thinking to cut the sill and wall below it in line with the jamps thereby creating the opening for the doors.

Is there anything I’ve missed? Someone suggested pouring concrete into the cavity to add some more support.

Any advice would be appreciated.

Google Image Result for https://www.mcmonaglestone.com/media/catalog/product/cache/2460e42ca1b7231eac065d16514821d3/s/a/sandstone_surrounds_3_.jpg

 

[Bonni]

The jambs are normally stood in place, so they'll fall out when you remove the sill. Looks kinda newer build.

If you just cut through the sill to leave two bits under the jambs, that look utterly crap. Pour concrete into the cavity? That someone is having a laugh at your expense if you did that.