Neither or. I'd like to see the frame as it was designed, and still see it after insulation and coverboards are added. Add add-on/knock-on to the survey where needed. Not lose most of the frame. !! Mr. HandyAndy - Really
To ALL , don't add add-on/knock-on unless you need them. Sean are this old units, picture not 100% clear but looks like external beading, not seen that in new windows for a while, plasterboard surround looks good and as good as UPVC is who wants to see as much as it as possible, every client I have had, wants max glass and min frame.
Frankly, I think a frame that has been buried, looks buried, and looks like a mistake. And I think it is unnecessary. Mr. HandyAndy - Really
I'm not aware of the age/male/type of the units - I only posted the image to illustrate the logic and method of insulating a reveal, which is relevant to units of almost any age I agree, maximise the glass and minimise the visible frame - UPVC isn't attractive